Removing water-based paint from your brush is easy if you do it right after you finish painting. Otherwise to remove dried paint from a brush, whether its enamel, lacquer, oil or water-based, use paintbrush restorer. Put on your gloves, safety glasses and dust mask, then pour the paint brush restorer into a metal bucket. Soak your brush in it, until it looks clean. Then use a wire brush to remove any excess dried paint.