Hot water and soap will
work, or alcohol, just like any other wax. If your coin is thick, more than 2mm, it may require soaking in a soda mix for at least a week with at least two changes of solution. Don't close it up for about 3 weeks. I generally watch the coins in open air for that amount of time, watching for further out breaks. You can finish, ie wax, the coin, but watch for the reappearence.
Bruce