I have a bunch of metal detecting coin finds that are a mix of mine and those of a good friend. I don't have any silver in this batch. I'd like to try and clean them up if possible but without ruining what little value (if any) they may have. I tried a method I saw online of freezing them in distilled water and then thawing. The idea was to keep repeating this and eventually the dirt will separate from the coins as the ice melts. I did it like four times and saw little, if any improvement. So do you think there is anything I can do to clean these up? Or is it pointless because they're pretty much worthless anyways? As always, appreciate the help!