Black spots

This has probably been gone over many times however, I have this black spotting occurring on the Australian half penny and wondering if there is any way to safely clean it? Also have another halfpenny that has a completely black color, normal? (have heard that acetate might work)

Sorry, but the black area on your coin is permanent, so either learn to live with it or get another coin.

Acetone (not acetate) will remove PVC slime. It will do nothing for either verdigris or corrosion.

Acetate plus water (acetic acid or vinegar) will clean your copper coins but it will also ruin it. Unless you pay through your nose you can't clean copper corrosion without also destroying unaffected copper surfaces. What might work for a pot won't for a coin.

Thanks for your answers. Looks like I may have to live with the discoloration. Strange how some older half penny's look almost new while some get this black (or green). Just oxidation and luck I guess.