I like Ruger Redhawk' s idea as well, go with the RIG and the sheep skin.

Oh Man,I can' t handle all this attention.First Vapodog and now Bigbore1895 liking my suggestion.LOL. After using my sheepskin I store it in a Zip-Lock bag.It keeps it clean and ready to use the next time.RIG is inexpensive and goes along way.A bargain at twice the price.
Ruger Redhawk

you could also try a reloaders case polishing cloth. it has a pretty mild grit to it and has buffed out some minor rusting over the years.the key is prevention. as soon as you get out of the field or home the first thing you should do is get it out of the case and wipe it down. those egg foam linings in gun cases hold the moisture to the gun. i have also switched to the birchwood casey synthetic oil in the spout can and love it. no smell and great in cold weather. it leaves a nice film on the metal parts without feeling too slick. i always wipe down the barrel as i was told the oils in your hands will do damage to a dry gun.