Selling your gold to one of those companies advertizing cash for gold, you are lucky to get 1/3 the scrap value.

Old jewelry of good design is way up in price over what it was ten years ago. Do not sell your antique jewelry to the 'cash for old ...' but try and find a reputable antique dealer who will help or pass it on to your favorite young'un.
Old gold-case watches, if the movements are quality and are still repairable sell to collectors for very good money. A good Hamilton or other good pocket watch in gold case makes a collector drool- and pay much more than the gold value..

Be careful of buying at Ebay or anywhere else on the net unless you know values. Occasional bargains, but many out there who know how to pitch their stuff to get the highest return.
Cheaper jewelry has the largest percentage mark-up.

Simply heating 9 carat to get purer gold doesn't work; the copper or other alloy metals must be separated out.
This site has workable methods of refining your gold, but they are messy, and some are toxic if care not taken.
http://shorinternational.com/refining.htm#Simplicity