I walk in my gun room today and find that my colt 1991 has a thin coat of rust on it, all my pistols are displayed on a book shelf kinda thing so its open, my glocks were perfectly fine but the colt didnt like the humidity, im guessing its the display case since all my surplus rifles look good since theyre in display cases with silica gel packs inside. Will coating the 1991 with clp fix this? How do you guys keep your guns rust free?