How to clean various coins including different metals and bi-metallic coins.

I am glad that i had found a group related to coins, (hope this group is related to coins).

I am not a coin collector and i have no much idea or knowledge regarding the coins and their values, however i am a traveler and i had traveled to lot of places because of my work nature and in a course of time i have accumulated large amount of coins as changes from the airports after purchases.

All those coins are in used coins and non of them are in mint condition. Some of those coins looks really beautiful but dirty.

My question to the group is, how can i clean the coins with out damaging the quality of the coins??? i have 500+ coins from 30+ countries. some of the coins are bi-metallic and some coins are of different metals which i am not sure about.

i have some interesting currency notes as well with expiry dates printed on them. I am looking forward to post about one coin/note at a time and make this into a hobby. I do have a very large collection of stamps, just mentioning.

waiting for your valuable guidance and comments on this.