A white spirit brush cleaner is a product that you can find at any hardware or paint store. Pour about 2 inches into a clean empty can wide enough to hold the dirty brush. Place the brush on a piece of newspaper and gently run the back of an old knife or scraper along the bristles from top to tip, scraping off any surplus paint. Place the dirty brush in the can with the cleaner bristles down, and allow it to soak for 20 to 30 minutes.
Holding the brush by the handle, work the solvent thoroughly into the bristles in order to free any enamel paint.
Hold the bristles under a warm tap and wash out all of the solvent.
Repeat steps 2 and 3 using a second can with fresh white spirit cleaner. When all of the solvent has rinsed out, wash the brush in warm soapy water, rinse, shake free of water, and hang up to dry.
Store the white spirit cleaner used for cleaning brushes in a screw top jar. The paint will settle to the bottom of the jar, and the solvent can be poured off and used several times over.