I torture my brushes
I leave them soaking in water for weeks on end.
I grind them into the dregs of past at the bottom of the glaze bucket.
I leave them outside for seasons on end.
Often they don't survive.
The ones that do seem to be the "natural materials" ones.
Today I went hunting for new brushes online.
I am fairly certain I know where I will be buying some now.
Check this Magical Place out!