There’s a specific kind of excitement that comes with a fresh syllabus. New sketchbook, new brushes, that first studio session where everyone’s claiming their spot at the easels. If you’re heading into a painting class this fall, whether it’s your first studio elective in high school or a serious oil painting course in college, your supply list probably has one line item that nobody explains well: solvent.

It just says “odorless mineral spirits” or “thinner” and leaves you to figure out the rest. So let’s actually talk about it.

Why you need a thinner in the first place

If you’re working in oils, you’re not just squeezing paint straight from the tube onto canvas. You’re thinning it out to control consistency, cleaning your brushes between colors, and breaking down old, dried-up paint at the end of a session. That’s what a solvent does. It’s not optional equipment, it’s part of your daily kit, right alongside your palette knife and rag.

The problem is that the classic choice, turpentine, is strong, fast-evaporating, and has a smell that lingers in your clothes, your bag, and honestly your memory of the whole semester. In a shared classroom with twenty other students working at once, that adds up fast.

A milder option for shared studio spaces

This is where something like Eco-House’s 115 Extra Mild Citrus Thinner earns its spot in your kit. It’s a medium-strength, general-purpose thinner made with purified mineral spirits and orange peel oil instead of harsh chemical solvents. Two things make it worth knowing about before your first class:

It’s slower to evaporate than turpentine. That sounds like a small detail, but it means your paint stays workable longer while you’re mixing and blending, so you’re not racing the solvent to get your color right.

It’s built with classroom use in mind. If you’re in a studio with limited ventilation, working next to other students for hours at a time, a milder solvent isn’t just more pleasant, it’s a genuinely more comfortable way to spend a semester.

One honest caveat worth knowing: it’s not suited for dissolving hard resins like dammar or copal. If your coursework has you working with those, you’ll want a stronger solvent for that specific step. For everyday thinning and brush cleaning, though, it’s a solid daily-use option.

Building the rest of your kit

While you’re stocking up, a few things pair naturally with your solvent:

• A closed glass jar with a brush basket insert, so you’re not left swirling brushes in an open cup and breathing more fumes than you need to.
• A stack of lint-free rags, since you’ll go through more than you expect in the first few weeks.
• A small palette knife, for mixing and for scraping your palette clean at the end of the day.

None of this needs to be expensive or complicated. The goal for week one is just having what you need close at hand so you can focus on the actual painting, not on hunting for supplies mid-class.

A good habit to start now

However you set up your kit, get in the habit of working in a ventilated space and keeping your solvent jar covered when you’re not actively using it. It’s a small routine, but it’s one your future self, and your lungs, will thank you for by finals.

Fall semester always brings that reset, the feeling of starting clean. A little thought into what’s in your solvent jar is a simple way to make sure the whole semester feels that way too.

Maya
Eco-House Studio

 

Here is something we probably should not lead with: our own citrus thinner has a smell. It smells like oranges, which most painters like, but liking a smell is not the same as not breathing it. So when the industry tells you that switching solvents will fix your studio air, understand that we are part of that industry, and that it is only a fraction of the truth. The smaller fraction.

 

You already know this, or you would not be reading. You switched years ago. Odorless mineral spirits, maybe, or all the way over to a citrus thinner. And the room still greets you the same way it always did, that faint sharp note when you open the door on a Monday after being gone since Friday.

 

Two things are usually happening. The first is that you stopped smelling it while you were in there, because the nose gives up on a constant odor within minutes. Coming back after two days is the only honest test you get. The second is that the bottle on your bench was never the main source.

The turpentine you did not know you were still using

Start on the medium shelf, not the solvent shelf.

 

Traditional damar picture varnish is damar resin dissolved in turpentine. So is most retouch varnish, which is the same thing at a higher dilution. So are the older copal and mastic mediums still sitting in a lot of studios. Alkyd mediums are typically carried in petroleum distillates. Cold wax medium is usually wax cut with mineral spirits.

 

None of those bottles say “turpentine” on the front. Several of them say it on the back, in the ingredient panel, if the maker prints one at all.

 

A painter can pour out the last of the turpentine, feel good about it, and go right on brushing a turpentine solution across the surface of every finished canvas at varnishing time. That is not carelessness. That is a labeling convention that hides the solvent inside the product rather than on it.

 

Turn over every bottle on the medium shelf and read the back. If a maker will not tell you what is in it, that silence is the answer.

 

(For what it is worth, we sell damar varnishes, #952, #953, and #955, made without turpentine. We would rather you check your current bottle first and find out you are fine.)

 

While you are standing at that shelf, there is a second question worth separating from this one. What is in the medium is a safety question. How much of it you should be using is a craft question, and it is the one behind dull passages and brush marks that will not level out. We wrote a short guide on that side of it: the Oil Mediums Guide. It covers proportion and handling, not ingredients, so it answers the other half.

The rag pile is doing more than you think

Oil-soaked cotton is the most underestimated object in most studios.

 

A rag that wiped a brush is carrying oil, not just solvent. Solvent flashes off in hours. Oil does not leave; it oxidizes, slowly, for weeks, and oxidizing linseed oil throws off aldehydes, which is exactly that faint rancid-sharp edge people mistake for old turpentine. A folded rag in a closed bin will outlast the can of thinner that made it.

 

There is a fire problem sitting on top of the odor problem, and it is not theoretical. Linseed oil generates its own heat as it cures. A balled-up rag pile in a lidded bin holds that heat against itself and can reach ignition without an outside flame. Studio fires start this way every year.

 

Lay rags flat, separated, on a nonflammable surface until they are stiff and dry. Then bin them. If you cannot lay them out, submerge them in water in a sealed metal container and take them out with the household hazardous waste. Not a plastic bag. Not the corner.

Brushes hold on at the heel

A brush can look clean and still be loaded.

 

Solvent and oil wick up past the belly of the bristle into the heel, the packed base where the hairs enter the ferrule. A rinse cleans the part you can see. The heel keeps a reservoir, and a jar of “clean” brushes standing bristle-up on the bench is a row of small open evaporators.

 

It is also what ruins brushes. Dried oil at the heel splays the bristles outward and no amount of shaping brings the point back.

 

Wash with soap and warm water, work the lather into the heel with your palm until the suds run clear rather than gray, reshape, and dry flat or hanging down. Not upright in a jar, where water runs into the ferrule and loosens the glue.

Surfaces absorb, though probably not for as long as you have been told

You will read that a studio which ran on turpentine for a decade is still exhaling it years later. The honest version is more limited than that.

 

Porous materials do take up solvent vapor and release it back. Indoor air researchers call it the sink effect and it is well documented. But for the light solvents painters use, most of that reservoir empties over days and weeks, not a decade. A wall is not a slow-drip turpentine dispenser in 2026 because someone painted in front of it in 2011.

 

What actually accumulates over ten years is film. A thin varnish of atomized oil, resin, and pigment on the shelf edges, the wall behind the easel, the taboret, the light fixtures, the dust itself. That film is oil, and oil oxidizes, and oxidizing oil smells. That is the layer worth washing, and it responds to soap and water in an afternoon in a way that drywall never will.

 

We would rather tell you the mechanism we can actually support than the more dramatic one.

Airflow does more work than the bottle

Switching to a milder solvent improves your baseline. It does not touch the habits you built around the old one, and the habits are usually the binding constraint.

 

Most studios do not have ventilation. They have a fan. A fan in a closed room mixes air, it does not exchange it. Exchange requires two openings and a pressure difference: something pulling air out, and something letting fresh air in on the far side of you, so the draft crosses the bench rather than swirling around it.

 

Put the exhaust low and near the work. Solvent vapor is heavier than air and pools at bench height and below, which is roughly where you are breathing when you are seated and leaning in. Put the makeup air across the room, behind you, so the flow moves from clean toward dirty and then outside.

 

And leave it running after you stop. Evaporation continues as long as surfaces are wet, which for a wiped palette and a rinse jar means well past the point where you stopped noticing.

 

While you are at it, cap the rinse jar. A settling jar left open is a continuous evaporator running twenty-four hours a day, and it is the single most common source we hear about once people start looking.

If you are going to change a bottle, change the right one

This is where most articles like this one would tell you to buy something. We will make it useful instead, which means saying the part that costs us a sale.

 

Odor and petroleum content are two different problems, and they do not move together. Our ladder, honestly:

 

• #115 Xtra Mild Citrus Thinner. Mild, faintly citrus. It contains isoaliphatic hydrocarbons, which are refined petroleum distillates, along with food-grade orange terpenes. It is gentle. It is not petroleum-free, and we will not print that it is.
• #125 NeutralThin Odorless. If odor is your actual complaint, this is the bottle. It is the quietest thing we make.
• #915 Natural Orange Terpene. The only petroleum-free solvent on our shelf. It is also the strongest smelling one, by a wide margin.

 

Read that list again. The bottle with no petroleum in it is the one you will smell the most, and the one that smells the least is not the purest. If a company tells you a single product solves both problems at once, they are selling you a story.

 

No solvent is ever perfectly safe. Not even ours. What a mild, fully disclosed solvent buys you is not immunity. It is a quiet baseline, and a quiet baseline is diagnostic. When your thinner is not contributing much odor of its own, the smell that remains is information. It is telling you about a rag, a heel, a jar, a film on the shelf.

What to check, in order

1. Rinse jars and any container without a tight lid.
2. The rag bin, tonight, before anything else. Fire first, odor second.
3. The heel of every brush in the jar.
4. The medium shelf. Read the backs of the bottles.
5. Airflow: two openings, exhaust low and near the bench, running after you stop.
6. The film on shelves, walls, and fixtures near the easel. Soap and water.
7. Last, and only last, the solvent itself.

 

A studio that ran on one set of habits for ten years will not clear in a weekend. But the smell does go, and it goes when the source is dealt with rather than covered. Scented candles and air fresheners do not remove anything. They add a second smell on top of the first and take away the one signal that was telling you something.

 

We have been making solvents since 1988, and we print every ingredient on every label, including the ones that make the product harder to sell. This is why. A painter who knows what is in the bottle can reason about their own room. That is worth more to us than a claim we cannot stand behind.

 

If you want the chemistry sitting underneath all of this, we went through it at length in Turpentine, Odorless Mineral Spirits, or Citrus: How Oil Painting Solvents Actually Differ. That one is about what each solvent is. This one is about everything else in the room.

 

Care for the studio. Continue the art.

 

Eco-House

 

Creativity without limits.

There’s a particular kind of dread that shows up at the very end of a painting. The work itself is done. The color is right, the composition resolved, weeks or months of effort finally sitting still on the easel. And then comes the last step: varnish. For a lot of painters, that final stage is also the one that fills the studio with the sharpest, most eye-watering fumes of the entire process.

 

That’s not a coincidence, and it’s not just in your head. Varnishing has quietly been one of the most solvent-heavy steps in oil painting for centuries, and most painters have simply accepted it as the price of a protected, finished surface. It doesn’t have to be.

Why varnish smells the way it does

 

Picture varnish exists to do a specific job: seal the finished painting, saturate the colors back to the depth they had when wet, and create a removable layer that protects the paint film from dust, grime, and UV damage over decades. Traditionally, that protective resin — often damar, a natural resin harvested from tropical trees — has been dissolved in turpentine or petroleum-based solvents to make it brushable.

 

The resin itself isn’t the problem. Damar has been used in picture varnish for hundreds of years precisely because it dries clear, stays flexible, and can be removed by a conservator generations later without damaging the paint underneath. The problem is what it’s been dissolved in. A strong solvent carrier means a strong smell, and a strong smell in an enclosed studio means real exposure, whether or not you’re still consciously noticing it by the time you’ve capped the jar.

 

That’s the part worth sitting with. Varnishing usually happens indoors, often in a smaller space than you paint in, frequently at the very end of a long session when you’re tired and less careful about ventilation. It’s exactly the wrong moment for the strongest fumes of the whole process to show up.

 

A different way to get the same result

 

Eco-House Damar Picture Varnish #952 uses the same time-tested damar resin painters have relied on for centuries, carried in a solvent system built around the mild citrus base that runs through the rest of the Eco-House line rather than a harsh petroleum or turpentine carrier. You get the same clear, protective, removable film. What changes is what you’re breathing while you apply it.

 

That matters most in exactly the situations where varnishing tends to go wrong: a small home studio with a door closed against draft, an evening session after the kids are in bed, a batch of finished canvases you’re varnishing all at once before a show deadline. Those are the moments a harsh solvent does the most damage, and they’re also the moments a mild carrier makes the biggest practical difference.

 

Getting it right still matters

 

None of this is a case for skipping care altogether. A varnish layer, however it’s carried, is still a chemical step, and it still deserves the basics: apply in a ventilated space, keep it off wet or tacky paint layers, and follow the manufacturer’s guidance on how long a painting needs to cure before it’s ready for varnish at all. Rushing that timeline is the most common way painters end up with a cloudy or uneven varnish film, regardless of what solvent carried it there.

 

The honest case for a mild-solvent varnish isn’t that it removes every consideration. It’s that it removes the worst one — the sharp, lingering fumes that make the final step of finishing a painting feel like something to get through rather than something to enjoy.

 

For painters, that shift is bigger than it sounds. Varnishing is the last thing you do to a piece you’ve likely spent weeks or months on. It shouldn’t be the moment you’re holding your breath and reaching for the window.

 

Eco-House Damar Picture Varnish #952 is available in a range of sizes at eco-house.com and through Amazon.

 

Eco-House Studio Since 1988 Care for the studio. Continue the art.