I really can't add too much here. Just to say that iron has an incredible affinity for oxygen so anything with iron in it will begin to rust almost immediately. certain types of steel like stainless and chrome steel are highly rust resistant but they still can rust. With razors the very edge of the blade which you can't see with your eye will begin to develop microscopic rust within minutes of exposure to the air. Its best to keep some oil on a carbon steel razor however if you use the razor everyday or even every few days the stropping process should remove this rust.