I use Challenger degreaser. Spray on and immediately rinse off. Its the first thing I do with really dirty bikes. Cuts thru everything fast and leaves the bike shining. I only had one instance where Challenger left some etching marks. That was on a very compromised crankset that was used on a commuter in the winter, lots of salt. So some reaction with the salt residue. It will eat thru paint on bikes that are really weathered. I've used it on tires, brake shoes, brake hoods, all with great success.