Need To Pre Treat New Uncirculated Coins?

Gunk or grim from circulation that gets stuck in crevices and in lettering is all but impossible to remove without a quick swish. The point is not intended to clean the coin in the classical sense, just to remove the junk and let the coin put it's best foot forward in your collection.

Most common is Acetone as it is a more aggressive solvent, yet it does not react with most coin's metal content. It evaporates so quickly that the rinse immediately afterwards is to prevent any residue from drying onto the coin that can sometimes form a haze.

You are not using the bathing method to disturb the natural patina or anything beyond reasons such as- breaking up tape, or sticky tape residues. Spot removal. Removing crud and build up in the legends.

First of all to the Forum
Glad your here.
As to playing around with Uncirculated coins it is not the greatest idea. For one thing to many chances of dropping them, scratching them, fingerprints or who knows what. leave well enough alone.
A coin in an air tight container should not change at all. If they developed spots or other problems, I would suspect the so called ari tights were not air tight. Just what kind of reaction would be from a piece of metal just sitting without any other substance in contact with them?
Also, if you do not presently have Acetone or other flamable substances in or around your home, don't start now. A coin or two is not worth the cost of a new home, your eyesight, etc. And remember those that do recommend this will not pay for your new home, you medical bills and will not even visit you in the hospital.
However, if your determined to try that, use the search tab at the top for Acetone and find the many explanations on that subject.
I still say leave well enough alone. I've put all types of coins in my Albums including proofs and never have a problem with anything. All my albums are in Zip Lock Plastic Bags.

I am confused about a water rinse after acetone yes or no. I could easily believe Thad about water. but will the acetone leave a film even if dried ?

for one thing it should be cleared that we are talking about distilled water. The massive variances in tap water could do excessive damage to coins. Actually some tap water kills plants if the water is run through a water softener.
Acetone will disolve lots of STUFF. One of the problems is when it evaporates, some of the disolved substances are left on the object that was to be cleaned with the Acetone. If the Acetone was also used for other purposes or has been laying around for some time, when it evaporates it could leave more STUFF on a coin than was there previously.
As I said you really should do a search of coin cleaning, Acetone, etc., on this forum.

Every coin I add to my collection gets an acetone rinse before it joins the collection family. I don't rinse with water, but I do think- it is not a bad idea. The acetone rinse is to just clean off any possible oils or anything that may harm or tarnish the coin. Do take precaution with acetone, especially if you have children.