Paint Brush Tip
If a brush seems totally ruined and the hairs out of shape, wash the brush again, then dip the bristles in some linseed oil and reshape it. Now dip the oiled and shaped brush into water-soluble glue (I use Elmers glue) and let it dry for a couple of weeks (bristles facing up!). As the the glue is water soluble you can wash it off in warm water, no soap needed. Et voila... much useful life restored to the brush. I've found it works on all but the worst victims of brush abuse.