I have seen cleaned coins that were very appealling and were needed for my collection. Many times I was ready to buy when I pulled out the magnifying glass. Isn't it amazing what a magnifying glass can do for old eyes? It just kills me to walk away from a coin I have been dreaming about for years because some idiot decided to make it "more" presentable! Sometimes the best intentions don't always work out. I guess we all find out, in this hobby, there is a right way and a wrong way to do things.
When I was 12 I cleaned a dozen napoleons with sidol copper cleaner because I liked them sparkling
When I tried to sell them later I lost 5% of value because of the cleaning and they were generic coins ; probably sold for full price to the next client
So I asked myself what is dirty ? Fingerfat and dirt .
So I put the coins in a row on top of the kitchen cupboards
I was making french fries every day in those days .
I turned the coins over regularly for 2 months untill the were sticky as hell
I then went to the cellar and toke the dust from the wine bottles and smeared it on
till the coins were no longer sticky .
I then sold most of them to an exchange agent who does not take out a magnifying glass
on routing coins and I had won 5 % .
I still have a few of the coins cleaned in the 60's and it is impossible to see 50 years later
which coins were cleaned unless you take out 10X maginification
They retoned nicely .
My coindeling friend retones them with a bunsenburner in 5 minutes