Removing that bloody sprocket

+1 definitely un rota-fix it, doesn't do any damage to the bike if you use a rag, only way to put a cog on or off... do it all the time, don't know why anyone would do anything else

Ditto - not even any tools required. I will add that rag around the BB shell should be augmented by one around the chain stay if you're really, really prissy about the frame.