Oh, you don't clean the brush. You have to volunteer a brush to "take one for the team". So don't use a good one, because it's no good for painting once you've dipped it in Tenax. And you also need to use one that is made of real hairs, not man made fibres, because the Tenax will just melt the fibres together and make the brush no good for anything at all. And you need to work real quick with Tenax, because it evaporates super quick. Actually, too quick to use by brush very well. That's why I apply it with a technical pen or a touch-n-flow.