Virtually every artist has forgotten to clean a brush at some point in their lives. If your latest masterpiece resulted in a few brushes that seem permanently stiff with paint, you might feel like cleaning them is a lost cause. Fortunately, you can actually clean up just about any paint in only a few hours, no matter how old and hard it is.
Every Paint Has an Effective Solvent
If you know what type of paint is dried onto your brushes, cleaning them off will be a cinch. All you need to do is give them a good soak in the right solvent for that paint, and even brushes that are dried stiff will become easier to clean.
These paints are water-solvent, so you won't need special paint thinners to wash them off. Soak your brushes in water for a few minutes and gently scrub off loose paint with a soft brush. If the paint is too stubborn to come off right away, heat some water to a simmer and let your brushes soak for a few more hours. Stuck-on watercolors should come off easily afterward.
Oil paints aren't water-soluble, so attempting to wash them off in normal water won't work. Instead, use paint thinner or mineral spirits to loosen up old patches of oil paint. This should be fairly easy, since oils take so long to fully dry. Soaking your brush in thinner to get out stubborn paint is fine, but make sure only to soak the bristles. Never heat paint thinner or mineral spirits, and remember to dispose of them as you would other hazardous chemicals.
Wood varnishes and some model paints are based on shellac, an organic resin. The best way to dissolve a shellac-based paint is to soak it in rubbing alcohol and then scrub the bristles gently with a brush. Even hardened varnishes should dissolve fairly quickly when dipped in the alcohol. .
When it comes to cleanup, acrylics function like a combination of watercolors and shellacs. They are both water- and alcohol-soluble, so either liquid can be used to clean them. Alcohol will usually do a better job due to its strength. Soap and water are useful for loosening up the paint initially, however. Try following the instructions for watercolors to get off most of the paint, then you can do an alcohol soak for the remainder.
Solvents Aren't the Only Option
Very old and hard paint may be too stubborn to come off in some cases, even after a good soak in the appropriate solvent. Don't worry though, you don't have to throw away a brush that stayed stiff after the first round of cleaning.
A popular solution for even the oldest and toughest of stains is a good old-fashioned white vinegar soak. In a pot, bring some vinegar to a low simmer and put your brushes in. Let them soak in the hot vinegar for a good hour or two, and the paint should be cleaned off. Since vinegar's cleaning properties are due to its acidity, you can use it to clean up any sort of old paint.
Another general paintbrush cleaner is fabric softener, which helps the brush release paint by softening up the bristles. Mix softener and water in a clear container and gently stir with your paintbrush. Paint should come off and drop down to the bottom of the container, so just continue stirring your brush around until it's all off. A gentle rub with a rag or paper towel should get off any remaining softened paint.
While they may be a little more complicated to clean than wet brushes, stiff ones aren't always a total loss. Give your problem paintbrushes a good solvent soak or vinegar bath and you might be surprised just how new they look in the end. For more information or assistance, contact local paint supply stores.