I know that I am new but.. just a thought.. Take a little plastic box add a little cotton and a little card explaining where the coin was found, and a little history then add the coin. Personally I belive that what has happened in history can sometimes be nasty... but that does not mean that we wipe every mention away or pretend that it didnt happen.
Sometimes you have to look at an item for what it is.. in this case it is a coin from the nazi era and nothing more. It is like just because you buy items from China... does that mean that you are for the human rights violations that the country commits? Of course not.