John,
You could process them a lot cheaper than using up your good nitric by using the crockpot and HCl. AP should do the trick also. Nitric is by far the fastest way.
Assuming the pins are copper based, the amount of nitric you're using should be about right. The copper nitrate formed works great as an electrolyte for processing sterling silver to prepare it for the silver cell. Use the copper nitrate after filtering it when you are done with the pins reaction, the anode is made from the sterling silver scrap melted into a bar and the cathode is a piece of hard graphite or copper mesh (I prefer the graphite).
Dry Copper nitrate crystals can also be used to make more nitirc acid by decomposing them around 175 C and bubbling the NOx vapors through distilled water.
Steve