Like others have said, they should be okay as long as you don't rub with a cloth or brush. A light finger rub is okay as long as you have washed your' hands thoroughly to remove any body oils and salts. Now, if you use any type of soap on them, then many soaps leave a film on the coins that can change the color from Red or RB to hues of Blue, Green, Purple and Violet or combinations of any or all of them.
Frank