It’s a pain reaching for a paintbrush only to discover that the bristles are a hardened mass because you didn’t properly clean the brush after the last use. Then it’s off to the store to buy yet another new brush. Fortunately, cleaning a paintbrush isn’t rocket science. It just takes a little diligence. Think of the brush cleaning as part of the overall finishing process. It also helps to buy quality brushes so you’re more inclined to want to reuse the brush.
Here are the basic steps for cleaning a paintbrush:
- Wipe off any excess finish using a clean cloth or rag. It works best if you squeeze the brush near the ferrule and work your way toward the end of the brush. Don’t pull on the bristles. You can also paint out the excess finish onto a piece of scrap wood.
- Rinse the brush in the appropriate solvent for the type of finish you’re using. For oil-based finishes, such as polyurethane, use mineral spirits, or paint thinner. For shellac, use denatured alcohol. For water-based finishes, use warm water. I read somewhere not to use hot water because it will expand the ferrule and allow bristles to come loose but I have never experienced this firsthand. A mason jar or other glass jar with a metal top is handy for storing left over cleaning solvent, allowing you to get more than one use out of it.
- Clean off the solvent-soaked brush with your rag or try the spin technique. This involves holding the brush between your hands, lowering the brush into a can or bottle, and then spinning the brush by moving your hands back and forth in opposite directions. Just make sure the brush is well inside the container or you’ll end up all splattered.
- Continue the cleaning using warm soapy water. Liquid soap works well for this. Suds it up and knead the bristles with your fingers, working the residual finish out. Then rinse off the suds and repeat the process until the water runs clear. This may seem to take forever but have a little patience. It feels a little strange to clean an oil-based paint with soap and water but it actually does work.
- After the final rinsing, dry the brush with a paper towel. Give it a good squeeze. Then, wrap the brush in its original package, brown paper or a paper towel. This will keep the bristles from fanning out, retaining the shape of the brush. Store the brush on its side or upright with the bristles pointing up. Do not store it upright with the pressure on the bristles.
Brush Cleaning Tips
Dip the brush in the appropriate solvent before loading it with finish. This will draw solvent up into the ferrule region, making it much easier to clean the brush afterwards because it prevents the finish from drying on the brush during use.
Use the proper type of brush: Natural bristle or specially-made synthetic brushes for oil-based finishes and synthetic brushes for water-based finishes. To be more specific, a natural black china brush is best for oil-based paints, enamel, and primers. A white china brush is a good choice for oil-based varnishes, polyurethane and stains. Shellac works best with a white china natural brush. Don’t use a natural brush with a water-based finish because it will absorb water and lose its shape.
Do not overload the brush with finish by dipping it in all the way to the ferrule. Not only does this create a mess but too much finish gets into the ferrule making it a pain in the you-know-what to clean.