Don't do anything until you understand the processes, the problems you will likely encounter, and you understand the dangers and how to protect yourself and others from the risks to health and safety, and you understand how to treat and dispose of the toxic hazardous waste.
The silver alloys will not dissolve in aqua regia.
Nitric will dissolve the silver and the base metals, gold if any will not dissolve, depending on percentages PGM to silver some can follow silver into solution or remain insoluble with any gold, you can recover silver from the solution using copper metal which the silver can be washed and melted, or you could recover silver from solution by precipitating the silver out as silver chloride which would need other processes to convert the silver salt to the metal before melting...
