Cleaning or restoring old shotgun

[BPTactical]

No steel wool or scotchbrite, too abrasive and it will take what is left right off. I wouldn't even do the denim.
Just put some CLP or fine oil like a 3 in 1 on a soft cloth and wipe the metal down. Just a guess but it looks as if the original finish was browned.
Just preserve what is there.
Just go with boiled linseed on the stock, tung oil has hardeners in it that the original finish was unlikely to have. Wipe the stock down with a lightly damp rag and let it air dry for a few hours. The put a drop or two of linseed oil on the stock and rub it in with the heel of your hand.
Is that an old Greener?