The coin/jewelry route with someone you know should work fine. No paper work. No problems. It should be considered a personal transaction as long as the dates are right for coins (pre 1933 I think).
Pay attention to what you're getting (at least 70-80% of numismatic value properly graded and no less than 8-10% below spot for bullion). And, be circumspect about how much at any one time.
Oh, and remember to declare any profits on your taxes.