Hey Carl... Funny you should say that about the window sill! I had several Ancient coins that were sent to me really overcleaned, I had them on the sill for almost 3 years, turning them every month. I was surprised on how the started to "patina up" (for lack of another word). That is almost exactly what I did with these coins. They are out on my knick-kack shelf by the window...
~ Wolfie