You had asked me this in a private conversation which I had yet to answer. So now I will answer this here. Peracetic acid has no use in refining that I know of and I hesitate to give you a "well this may work answer" and have you hurt yourself. The exposure limits for this chemical are very very low and the bodily harm it can do you is substantial.Could one use peracetic acid to cause the copper and other non-PM to go into solution before rinsing leaving the PM precipitated?
You will be better served to tell us what you have and what issues you are having refining it and learn to proceed along a safer route.