Everyone Says Cleaning Coins Halves Their Value - What the 1-70 Grading Scale Really Reveals

https://wiki-zine.win/index.php/When_a_1933_Double_Eagle_Sold_for_Over_$18_Million:_How_That_Moment_Changed_Estate_Sale_Coin_Buying

Which questions about coin cleaning and the 1-70 grading scale will I answer - and why they matter? You hold an old coin and someone told you that rubbing it with a cloth or a kitchen cleaner destroys half its value