My friend asked me to find her an old bike to use as a planter in her yard. Well, I found a throw-away at the LBS - a 1936 model (no badge) which was nicely rusted in most areas. In order to enhance the effect, I stripped all the remaining paint with a sander. I then sprayed 3% peroxide solution and sprinkled on some table salt. Instant rust! Gobs of it! Lookin' good!