The life for a brush can be a bit difficult. I try to be kind to my brushes but sometimes I forget to rinse them in a timely manner. They sometimes sit in water over night or they don’t get rinsed completely. Sometimes soaking the brush in fabric softener will bring them back to life. There are some other products available to clean brushes but I find that most of them are fairly harsh and can destroy the handles (and probably the environment too). I like products that clean and polish. If none of these things work, then the brush must be buried at sea. It’s an opportunity to find a new brush that’s up the challenge.