Mattie, that is what this forum is about, but it is not as easy as you make it sound, there are many details involved to separate the metals from each other this is done through many steps and several different processes.
All melting would do to the jewelry is oxidize base metals in the metal, and make it harder to make jewelry out of it again, but we would melt it with silver to lower the karat, to about 6K, the reason is we need to remove base metals from the gold, nitric acid will dissolve these, but if the gold ratio is too high the nitric acid cannot get to the base metals in the metal as gold will not dissolve in the nitric acid, if gold content is too high the nitric cannot get the silver and copper and other base metals under the layer of gold, by lowering the karat and raising the silver content we give a path under and into the gold where nitric can remove these metals.
Once we remove the majority of base metals then we recover silver from this solution, we use copper metal to replace silver from the nitrate solution, to recover silver, we can reuse it to melt with more gold in an in-quartering process, or refine it in an electrolytic cell, or use it in some other process.
the gold is then refined by dissolving it, and precipitating it from solution as a more pure product, it goes through a washing procedure and then is dissolved again and precipitated again washed and melted.
The jeweler would then take the pure metals melt them in correct proportions to make his jewelry with.
most jewelers do not refine, most refiners are not jewelers.
I just gave a quick overview, of how it is done, to learn how to do it you will need a lot of study, Hokes book is where you need to begin that study, the book is here on the forum as a free download or better yet if you are serious but the book around $60 do not pay over $80 (easier to read and use and a great investment).
The forum will give you many tips to add to what you will learn from Hokes, which will make the process work better and smoother like how to use minimum acids to avoid troubles, how to wash the gold, or use gold to eliminate excess acid, how to treat waste, and just about everything to do with recovering and refining precious metals.
This is an art and a science that will take some time and commitment to learn, it is not something you will learn by getting a few instructions, it is a very complicated subject, and as with any art or skill or science, it takes much work to learn and get good at it, it can take years to learn, and actually the learning will never stop, because their is so much to it a man would not live long enough to learn it all, it can also be very dangerous, if not done properly as we are dealing with many toxic and deadly gases, and other dangers, and as with any chemistry a good understanding of the dangers and taking precautions is needed, these danger should not be taken lightly, even the solutions when we finish are very toxic and need treated for safe disposal, these solutions can be very deadly acids or salts, which in a water supply like a well or a river could kill or harm anyone who drank water from that source of water.
See the general chat section, welcome to new members and guide to the forum,
and see if these links help you get started, on your journey into this very interesting science of metallurgy.
C.M. Hoke http://tinyurl.com/mfnyhs
Waste treatment for the small refiner http://tinyurl.com/78z9v5a
http://www.scribd.com/doc/2815953/Refining-Precious-Metal-Wastes-C-M-Hoke
http://tinyurl.com/82ynbxb
Stannous Chloride Recipe and Testing Results
http://www.goldrecovery.us
http://www.goldnscrap.com