Vaseline Will Prevent Rust A coat of vaseline, mixed with a little camphor, is an excellent preventive from rust for tools. The mixture, before applied, should be heated over a slow fire. Apply the coating to the tools with a soft rag. Make sure that the tube connecting hot air stove and carburetor is a good one, without leaks or weak places. Its function is to carry hot air to the carburetor. If there are leaks the air will evaporate the gasoline, and the engine will lose power.