Cleaning 90% coins

[Know Common Cents]

Regardless of what method (or methods) that you try, practicing on junk silver is the way to go. Try several different chemical baths and see what works the best.

I'm not a fan of acids and the like, but it's interesting to see what works well. Good luck.

[everything]

Definitely .. try burning it, might get some nice toning besides.

I have a very nice barber dime, full liberty, very little wear. Some dark staining on the front. But on the back, is part of the book it must have been glued into back in 1905. I have had it soaking in acetone for 6 weeks now, often shaking the glass bottle. Not much improvement. Would paint thinner do better, or should I just give it a year in acetone, then give up? It is really a very nice coin, other than the bonus coin book stuck to the back.

Since acetone hasn't resolved the problem, step it up to something else. MEK, or gasoline, or TEC (do not mix together any of these). You can't hurt the silver unless you go to strong acids (don't do that).

[SilverDragon72]

So revisiting this thread about cleaning the 90% halves last year. They turned out just fine using a jewelry cleaner and patting dry with a towel. After almost a year, the coins still look great!
Can't say the same about the pennies I did with vinegar and salt. They were quite shiny for a while, but eventually returned to a reddish brown hue. Still clean though.