I store my bike on stands, clean rims good, making sure they are dry and then i liberally coat them with wd-40. I"ve been told wd-40 displaces any moisture that might build-up on them. I reapply wd-40 about once a month for the duration of storage, wash off and clean in the spring. Used this procedure for 5 years on my chrome rims and they remain pit and flake free. That being said a lot has to do with the quality of the chrome to begin with