I went for a ride on saturday, then put the bike in shed , on sunday morning I went out to give it a wipe over and the chrome pipes looked like they had rust spots!!! on closer inspection it appears to be either tar or some kind of resin residue that must have got on the pipes when hot, then cooled and stuck there. I can't budge them with my fingernail, and tried a small bit of car polish on a rag and that didn't do much at all. I dont think rubbing/polishing is gonna remove them and arn't keen to get too aggressive with that. i'm thinking i may need to try some kind of solvent? I was gonna start with turps, but before i do does anyone have any similar experience/ advice/product?