I gleaned this from a thread here some time ago:
This thread discussed wood cleanup:
http://www.16ga.com/forum/viewtopic.php?t=2224If the brls have not been cold blued, you can safely remove most of the corrosion on the brls using WD-40 and OOOO steel wool (some guys recomend 'bronze wool') or off the brls and receiver where the case colors are already worn off using a copper penny and
Kleen Bore's Formula 3 Gun Conditioner-it's sold for about $3 in 2 oz. bottles.
Flitz will also clean up the metal but WILL remove case colors. I ended up needing to use some
Mothers' Billet Metal Polish to remove some rust from the trigger guard and was surprised that the blue remained.
Great care must be taken cleaning the case colors, I use
Flitz Gun Wax that both cleans (and brightens) and protects
http://www.flitz.com/After clean up, protect the wood and metal with
Johnson's Paste Wax or (even better but expensive)
Renaissance Wax http://www.restorationproduct.com/