there can be several methods to recover then refine the metals.
nitric is about the easiest, to remove base metals, silver and palladium can be recovered from the solution, the gas can be dangerous, nitric can get expensive,
a slower process for removing base metals would be the acid peroxide approach, slower, but less fumes, and the solution is reusable,
for pins there is also the concentrated sulfuric acid cell.
solder tin and lead can be a problem removing a little time removing these can save you time and fustration later, hcl, or acid peroxide will break down the solder brushing also helps, the lead will break down to white powder tin will go into solution,
remember any time you mix nitric and HCl in any quantity it will dissolve your gold into solution, even from the salts of either of these, inceneration will drive off these salts as gases.
the easiest for the beginner to dissolve the gold and to get it back would be HCL? Bleach method
the fastest is Aqua regia.
have you studied HOKES? also I suggest to collect the material and study well just doing expieriments to see how different metals react in the different acids, practice makeing and useing test solutions,
once you understand the safety issues and safe disposal of your waste products, and have a good grasp of the different techniques and the problems assosiated, you will have a good supply of material to handle and will have the understanding to handle it without wasting your gold and doing dumb things. diving off this bridge in this cold water without knowing what you are jumping into is not a good Idea.
start with something simple like fingers follow the methods if you have to get started while your studying,
doggonit who would thing just getting a little bit of gold would be so much work and require an education?
but this is just my two penny's take em or leave em.
