Anyone got any suggestions for cleaning bitumen off paint brushes. They've been in a plastic bag for just over a week.

Currently got them soaking in white spirit, but it looks like it's going to take a while like that.

TBH I think white spirits will only soften it a bit, not remove it, but I can't think of anything else that would do it.
You can get some proper solvents that'll do the job, but I think you'd be better off just throwing the brushes away. Bitumen is a b!tch to remove from anything, usually the easiest way is by scraping - obviously not an option for brushes!

I seem to have got the worst of it out, certainly enough that they can be used for the remaining bits that need doing.

Annoyingly though, it has now started raining…