I’m not a perfectionist (who am I kidding? Of course I am!) but everyone makes mistakes when they paint. Some you’re happy to live with and others you feel you need to correct.
Although some painters use cotton buds to clean mistakes, I just don’t like doing so.
I prefer to use a flat or angle brush in a reasonably good condition to clean my mistakes. The chisel edge of the flat or angle brush is a great help in straightening lines, for example.
If your “spare” flat or angle brush is now a little "bushy" and won’t give you a reasonably good chisel edge when you’re painting, keep it for stippling trees, bushes, little flowers or for removing whole leaves or flowers from your painting. If your “cleaning” brush is in really bad shape, its not a bad idea to buy a very cheap flat brush (get a #8 or #10). Keep it specially for correcting your mistakes.
Sometimes we need to wipe out a whole area because we don’t like the look of what we’ve painted, or we accidentally dropped paint or smudged our work – for this, a small piece of sponge does the trick. If your wet palette sponge has got holes in it, don’t throw it away. Wash it well and dry it. Then cut it up into smaller pieces like 5cm x 5cm. Every time you sit down to paint, wet one of these sponges and keep it beside you. You’re ready to wipe away any mistakes you might make.