How do you clean a 12 gauge shot gun?

Answer 1

No one answer, since there is no one 12 gauge shotgun. Procedure will vary depending on type of shotgun- single shot, auto, pump, bolt action, over & under, side by side, etc.

A good start is to read the owner's manual. If you have a fairly recent made shotgun, you can (in many cases) download an owner's manual from the maker's website. You can also buy a cleaning kit at just about any gunshop. The kit will include a rod that allows you to scrub the inside of the barrel with powder solvent, and to dry it with cloth patches. You will also need a light lubricating oil (bought same place) to lubricate moving parts, and to lightly wipe on exterior metal as a rust preventative.

And step one for ANY firearm is to check that it is fully, completely, totally unloaded.