A quick question about acetone.
I'm in the process of cleaning up some coins with acetone. My question is about the duration of soaking a coin. I have a 43 D nickel sitting in acetone for the second day in a row. The coin has several small dark green spots that I'm certain are PVC. I've changed out the acetone 2 times and each time I come back a day later to greenish acetone. I assume this is the solvent slowly breaking down the spots since they appear to be slowly shrinking. My question is should I just soak this until my acetone isn't green anymore? Is there any harm that will come from soaking multiple days or a week? My last question is how do I determine the purity of my acetone? I got some from home depot but see no real mention of purity.