A month ago I cleaned my chain and re lubed it, mainly lubing the chain on the inside where the sprokets contact. I have just noticed there is a bit of surface rust on the chain, on the side plates, closest to the rear wheel. The lube obviously didnt get sprayed on the side of the chain. What would be the best way remove the surface rust? (Ive been told a wire brush can damage the chain) And also should I make sure that I spray the lube on both sides of the chain in future to stop this from happening?