Preserving Silver And Nickel Circulated Coins

Hi, I'm new to the forum, but I've actually visited it a number of times for different concerns I have with Canadian coins. I've gone through a number of cleaning/preserving topics but haven't found anything specific that I'm looking for, so I apologize if this comes off as obvious. So from what I've read and heard from different collectors so far is that the first rule of collecting is not to clean coins and the second rule is to refer to rule 1 if in doubt.

Most of the coins I have and collect have been circulated at some point during their history. I store all my coins in 2 by 2 holders. And from what I've heard is that over a long period the oils from your fingers can significantly damage the coin if not cleaned. So my concern is more with preservation of the coins rather than their appearance. When I give my coin collection to my grand children in 60 years, I want them to be in the same condition as when I stored them in their 2 by 2s.

So my first question is in terms of Canadian silver half dollars that are 80% silver and 20% nickel (same question applies to Canadian silver quarter and dollars that are mostly silver, i.e. pre 1967). I was told by a collector of 4 decades that its OK to clean these coins in Pro Dip Silver cleaner (pictured below) and the value would not be reduced at all. He said its OK to dip these coins in this as long as they are not proof likes.



So before I started doing some research, I took his advice and dipped the 1966 half dollar on the right (below) in the Pro Dip and it cleaned it nice and likely got the oils from human fingers off it, though it brought out a lot of the scratches. The 1942 on the right has not been cleaned with anything yet. So I want the forum's opinion on weather I should just leave my coins as I purchased them and not clean them with anything and accept the fact that over time these coins will likely rot and there's nothing I can do? Or is it safe to use the Pro Dip? Like I said, I want to preserve my coins for a long period, and don't want the oils from fingers and other stuff that has had contact with the coins to damage them over the long term.





I also read about a less chemical way to clean coins which includes using dish soap. Rub the coin gently in dish soap water, rinse under tap, and then rinse in distilled water and let air dry. What do you guys think of this?

Lastly, what about coins (toonies, dollars, half dollars, quarters) that are post 1967 and are either 100% nickel or steal plated? What should I do about preserving and storing these coins?

Thanks.