I have a Blissett .50 caliber muzzleloading single barrel rifle in about untouched original condition. It has beautiful engraving on it, but there are some small "orange spots" on the engraving. I don't know if it is old oil or a very light rust. What is the proper way to clean this up or should I leave it alone? I don't want to hurt the value of it. An old gun dealer friend (Wayne Eikenberry) told me a long time ago that he used 4/0 steel with gun oil on it to carefully go over the engraving to clean it up. Should I try this?

I would contact Barry Hands or Ken Hurst. They should be able to provide an expert opinion and advise the best action to take.

http://www.barryleehands.com/
http://www.singleshotrifles.com/kenhurst.htm

LD1, in the condition you describe I strongly urge you not to attempt any "cleaning" yourself! Contact the gentlemen above and ask for help. This is no time for experimentation. Please!

Here is a better picture of the patch box cover. The rifle is cased in it's original oak case with a full complement of original accessories incuding a spare fully engraved hammer and belted conical bullet mould. The rifle also has a set trigger. I am very apprehensive about doing any work on it, but I don't want it to deteriorate either. I will contact knowledgeable people before I proceed.

gun engraver bill mains told me while working on my beretta 687 EELL to use a green scotch bright pad rubbing lightly. seems to work well. just another idea from an old colt factory engraver. jeff

LD1:
The core question at hand is: Will any cleanup degrade the value and time honoured patina of the gun?

If the answer to that is "no," then 0000 steel wool moistened (not soppy!) with a bit of Hoppe's will do the trick without damaging the engraving. Keep a paper towel handy to restrain any excess that may damage the wood.

Best, Kensal

if it was case hardened that might just be old varnish i cant tell from the pic, but use oil and scotch bright and go lightly (you might need oooo steel wool)

Gentle application of bronze wool and/or a brass toothbrush, moistened with a bit of Hoppe's No. 9, should give good results without damaging any remaining finish or patina.

REmove from the wood and boil in a little whashing soda,rinse thoroughly ,this will clean of dirt and any varnish so you can see whats underneath .You may be suprised .I did this recently to an old action I thought was past hope only to fined 50% original colour under all the crap and dried oil.

If you can remove the item from the wood, I would boil in dishwasher liquid/powder and tap waterfor 5 minutes, then rinse well and dry thoroughly with gentle heat and/or compressed air. This will remove all the old oil and grease but not touch any colour hardening etc. If there is surface rust this will become very apparent after this treatment and you can decide how to proceed depending on the presence of any hardening colour. Obviously re-oil afterwards to preserve the finish.
I would strongly advice against using scotchbrite, the US version may be different from ours but my experience is that it strips blacking and browning a treat so I guess it will do the same for the hardening colour.

I agree this might be old varnish. However;I'd recommend varnish remover which is NOT abrasive before trying anything else. If varnish remover works I'd then go to a good quality paste wax to clean. Again; paste wax will clean and isn't really abrasive so any patina should remain.
My point here is to try and use the least radical method to restore an item while reducing the chance of damage.
Jim