So acetone doesn't react with copper, like it shouldn't or better said can't… but acetic acid formed under the presents of water as well as energy input and a high surface area catalyst over a very long time. And even acetic acid needs certain catalytic properties of certain copper compounds to react with copper.
Photochemical breakdown of acetone on copper The paper describes how acetone under certain conditions when used to clean copper can decompose possibly affecting analysis of the copper substrate by AES, XPS/ESCA or SIMS atomic surface analysis. The copper itself wasn't degraded.
I would have expected if the assumption that “copper reacts with acetone” were true it would have been much easier to get googled results stating that rather than this one esoteric scientific paper which doesn't really support that assumption at all.
Making the statement that copper reacts with acetone is just misinformation when it comes to cleaning coins using acetone. The harm is that there are people that will believe it because they read it.
Never use nail varnish remover, although it’s acetone based the added chemicals are harmful to alloys. Only pure acetone which can be purchased from a pharmacy is safe to use, I’ve been using it for years with excellent result.
