Many here and elsewhere seem to hold the belief that acetone can have an effect on the color of copper. I've also read that the apparent change in color that can happen on copper is not from the acetone itself causing the discoloration, but the acetone removing a film (contaminant) that is contributing to the coloration. I've been using acetone on copper for many years now. I've used acetone on circulated and uncirculated copper, early 19th century to modern, from fully brown to fully red, on business strikes, matte and mirror proofs, PL and semi-PL business strikes, an early 20th century copper pattern and a late 19th century specimen (both with colorful toning), and various copper medals. I have never, not once experienced a change in color on copper from the acetone. To those that believe acetone can change the color of copper - have you actually seen this happen yourself, or did you just hear about it somewhere? Has anyone here experienced this first hand that can share their experience (even better if you have before and after pictures)?