Don't do it! You will get FAR less than the value of your gold. First get a magnifying glass and look at each piece to determine karat weight. Here's a scale: 22K = 91.6% gold. 18 K = 75%, 14K = 58.33%, 12K = 50%, and 10K = 41.66% gold. You will need a small scale to weigh each piece to determine how much pure gold is in each piece. 480 grains per 1 troy oz of gold.
You can't expect to get the current value of gold from your pieces, currently about $950 per oz, but you should get at least 75% of the value. Your best bet is to go to a local coin shop that trades in gold, and know the value of your stuff before you go. They should give you a fair price for your stuff, but if not at least 75% walk away. The mail in places are ripoffs.