If you can appraise them, do so. If not, pay a dealer to do it, giving market value and wholesale value. This will give you an idea of the actual value. Then offer them in the GBO classifieds at a price between the 2. The dealer should be able to tell you what the "gems" are and they might be auctioned off. Perhaps they could be sold privately or put on consignment at the dealer's shop, or taken to a gun show (check laws and the gun show's policy).
My friend's father "left the range" a while and I was asked to appraise a considerable collection for the family. The shooting son and I bought a current blue book, and we appraised each gun at market value. He distributed the collection evenly, but only the pistol permit holders received the pistols, and everybody got rifles and shotguns. Well, the pain-in-the-*** brother in-law takes his share down to the local gun shop and comes back screaming that Dan is a thief since the dealer offered him less that the market value that we had put on the guns.
Another local dealer had a friend pass away and, after an appropriate period, visited the widow and offered to appraise the deceased's collection at no charge. The widow told him that she had always hated the guns and after her husband's death, she and a friend went out in a boat and threw the guns into a lake! She turned white when the dealer informed her that, the guns that he knew about, not the whole collection, were probably worth at least $40,000.00!