I'm curious, how do one determine or find out if a silver coin is dipped to clean in a solution? Especially if they Uncirculated coin.
Is there a test, of course not causing harm to the coin?
You generally look at the appearance - but on an uncirculated piece where the toning wasn't too heavy to start with, it may not be possible to detect a coin that was dipped quickly.
I personally don't have any concerns with dipping except on lower grade coins where the surface changes considerably.
What I do is an "eye test". From what I understand, an uncirculated coin has many microscopic peaks all over the face. These sharp peaks reflect light in all directions and give the coin that signature luster.
When a coin is cleaned, these peaks are eroded and turn into small mounds. The shine of the metal remains but it doesn't have the sparkle.
Unfortunately, I don't have any good comparison images. I have plenty of nice, uncleaned coins, but no images of cleaned coins because... well, I've been good about staying away from them! (I think).
I'm sure others will help out here too.