I have just started a new school and, going through the initial process of letting the students know my expectations, showed them how I want them to treat the brushes. Well, my hand fell onto the container and I picked up one that had dried with glue on it. I picked up another - dried paint. After a quick check I found that there was a sizeable proportion in this state. My question is - are these recoverable? I hate seeing brushes treated like this - my students at the old school knew better and so (now) do these but if they can be used for anything at all (other than tinder) it would be worth it. Any ideas?