This may disgust some of the OCDC people, but I found a steel multi-tool covered in rust and have left it that way, except that I rubbed with oil. The oil gave it a brown sheen and rendered it immune from further rust with normal use. It reminds me of the treatment British soldiers gave their "Brown Bess" muskets in the 18th C., although that treatment was a little more involved. I've seen the brown patina on other old tools. It may just be due to handling a slightly rusted surface. Kind of attractive, actually.