I have two cheap brushes that I am using until my new badger brush arrives, and one of them haemorrhaged a massive chunk of bristles today. I don't really care about the brush I just want to make sure I don't destroy my new one when it arrives.

When prepping for my shave I boil some spring water, put it in the larger of my two shaving bowls, chuck my brush in, put the smaller bowl on top, put my choice of shaving cream etc in the top bowl to warm up, have a shower then recover the brush, mix lather then shave.
It was at the lathering stage that the brush pooped itself, I have used this method with my other cheap brush with no trouble.
My new brush has a plastic handle so the water won't bother it, but will fully submerging it be bad for it, or was it just a cheap brush being cheap?
Thanks for your input