The problem with using water on an old gun like that is you can't be sure you will get it out of all the cracks and crevices, and the gun oil may not displace it. So then you get rust. The cleaning method for black powder guns means ONLY the bores, NOT the wood and adjacent metal. And it is specifically for black powder shooting, which I suspect is NOT what you've done with the bores in this gun.
My suggestion for cleaning everything metal BUT the bores is to get some bronze wool, the finest/softest you can find (big hardware stores have it) and some penetrating oil (I use Kroil). Then VERY gently remove any crud on the metal, using LOTS of oil and VERY LITTLE "elbow grease." "Patina" by the way, means just about nothing--one guy considers raving, wild red rust to be "patina" and another thinks it is a microscopic film of dried fingertip oil from last year's handling--"patina," like beauty, is in the eye of the beholder.
My advice is just to go slow, take off any loose stuff first, wipe down, and look. If it still looks like there's crud, oil up, rub lightly, then wipe off. When it looks right to YOU, stop. In my case that would be when the crud stops coming off easily. And that's WAY before you see any bright metal!
Hot water and detergent is a good way to clean the exterior of the stock and forend, assuming you can keep the water off the wood/metal joints and the metal. I use a soft rag for this to control the water, go slow as above. When done to your taste, wipe the detergent/water mix off with pure water, dry with a hair dryer turned not too hot, and then apply a light coat of stock wax. Removes organic crud like finger scum and dried on gun oil, stock wax buildup, etc. Use a used soft toothbrush to lightly clean out the checkering and dry that area especially well.
Good luck; a great heirloom deserves great care.
PS, the reason for bronze wool, not steel wool, is that it is slightly harder than crud and surface rust, and softer than bluing and browning finishes. Steel wool is harder than anything but the gun's metal itself: it can take off the exterior bluing or other finish.
Last edited by Mike A.; 07/28/11 12:15 PM.