Well there is a simple remedy, and it is the same like for rust. Keep it dry. All microbial live needs water just as much as larger liveforms. If it is dry it can't spoil, even if there is microorganisms on it. They might be alive, but they'll be in stasis without sufficent accessible water. accessibility is also important here. E.g. salty water or water with high amounts of sugar are not useful to most microorganisms.