Just remember these two:
Guitar picks are best tools for removing/disassembling/prying rubber and plastic components. In heat of the moment we usually take a screwdriver and partially destroy the stuff with it. Won't happend with a nylon pick. They are up to 2mm thick.
Cantilever braking surface on your rim can be easily clean with a 'gator grit'. It's a synthetic steel wool, give it a good rub, then degrease it with a degreaser (something like M600 or similar, you can get it in any auto body shop, usually the call it "silicone spot remover", it's for prep before painting - won't destory any rubber or plastics, it's very mild but effective) or soapy water.