1. You guys mentioned a "proper" way to clean coins So how do you do it 2. I mostly collect Chinese and US coins P.S. I didn't know how to use the quoting feature so I used this Thanks in Advance
I would leave it alone, cleaning is not going to improve the value, less people would want to buy it as cleaned too. Any photos? What is the date?
Search through CoinTalk and you will find posts on it. As a beginning, you can always use acetone and distilled water. Let the coin dry naturally after a dip in distilled water. Dipping can be done correctly but it takes time to learn how.
Before, when I was even more of a Beginner , I used Hydrochloric acid to clean my coins (they tarnished even more), is there a way to reverse the new tarnish?
Cleaning is mostly tricky and best left alone for most modern issues. The main offence you can commit in "cleaning" is to rub the coin with pretty much anything. On the other hand, soaking coins in pretty much any pure solvent is OK. These pure solvents could include distilled water, acetone and xylene. Actually cleaning/soaking in tap water isn't so bad as long as you rinse with some distilled water. Now about cleaning ancients...that's another story...
Hydrochloric acid and you are 12 years old!!! Where DO you live? Strong chemical reagents like this will etch or otherwise modify/disturb the surface and you are pretty much out of luck to reverse it. The increased tarnishing points out the fact that a clean surface is a reactive surface if you don't stabilize it in some way.
Depends on what you're dealing with, right? Supposing it's tape or glue. Acetone will cut through that. You could experiment on your junk silver coins. The big deal is you don't want to hurt the finish on the coin. Once you do that, you deaden it, and that's irreversible. Why don't you try cleaning some, then showing us? We'll let you know how you did. Get right in there in the driver's seat. That's one of the best ways to learn.