@rosalinta, first welcome to CCF. Second, the only thing that I would add is that you pretty much should not be cleaning your coins at all. It may make them shiny, but you will be removing their numismatic value.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz