The whole thing seems kind of shady to me, but I know that I've read on these boards that people have actually done it. I don't have that much to sell, but every little bit helps, right?
What I did was go to a local jeweler for an estimate. Then I sent away to U.S. goldbuyers. Soooo simple...they called me within 48 hours and game me an estimate which was higher than local jeweler. I accepted and they mailed me a check within a week!!! Very simple. And all it was was a few broken necklaces and charms and one kinked up bracelet. I think it was around $400...GOOD LUCK!!!