OK, here goes....I'm sure to be harassed over this but it works for me.
I wear penny loafers everyday (with socks) and several times during the day, I just drop my ugly Abes into my shoes that I'm wearing and let my feet do the cleaning. I guess the heat and moisture that builds up in my shoes really does the trick. I always wear socks so I've never tried it without socks. I discovered this one day in that I found a wheatie and didn't have a shirt pocket and my pants pockets were full of other coins. So I just dropped it in my shoe and when I got home, I was amazed at how shiny and clean it appeared. Doesn't work on every penny but sure does a number on at least 75%....plus I don't have to rub, scrub or soak in vinegar. I have to laugh because sometimes when I have several in a shoe, they clang when I walk. You may want to try if you just have a couple, trust me...more than a half a dozen or so and it can become a little uncomfortable. Thought you guys might get a laugh out of this....I sure do. Wife says "You're an idiot!"