If you read through the cleaning threads on the forum here you will see that we generally counsel against chemical methods. Stay away from rubbing alcohol and cola etc for cleaning coins.
Usually the best methods are to combine gentle mechanical cleaning with distilled water soaks.
I have done courses for kids age 10-13 at a Saturday am program at a school. They usually ran 6 weeks.
We would spend part of each meeting on theory - power point presentation with some basics on ancient coins
, what they showed, how to ID them , cleaning theory, etc - and then some actual cleaning time.
Cleaning sessions depend on the time you have in your class but I suggest something like:
During the first class start with triage. Determine if the coins needs to be cleaned or can be cleaned. Look at each coin while it is still dry.
If it has already been stripped of all dirt and patina then there is little that can be done to enhance it. If it has been truely stripped of patina and is all shiney or in bad shape then a gentle brushing with a SOFT brash brush will help bring out the details. However, NEVER do this with a coin that still has its patina on it or looks nice.
It may also have very little dirt on it and already be readable and look fairly nice. A quick brush with a soft toothbrush will do. Both these classes of coins are now ready for identification
and storage. Identification
is in some ways the most interesting part as you will link to actual history. Storage should be in either a small paper coin envelope (they can write the details on the outside) or a clear platic "flip" (the coin goes in one pouch and a label can be made to insert in the other pouch.
However, most coins will need cleaning.
For these you do a cycle of soak in distilled water and then clean (brush in circular motions) with 1) soft toothbrush, then 2) hard toothbrush made by cutting down the bristles of a toothbrush to 1/8 or 3/16 of an inch length, then 3) picking/scraping with a bamboo skewer. This cleaning is safest to do while the coin is still wet or damp. I would avoid any metal tools (dentail pick, pins, scalpels) until you do an advanced class with people who have done the above methods for some time.
You end each session by putting the coins in distilled water. A little plastic container with lid for each student. You write their name on top in indelible pen.
Thus for the first class you triage and then have to wet the ones you will clean. For each subsequent class you take them out of their tub wet, clean them, and then put them back in with new distilled water.
During each cleaning session they should check the coins at the end and determine if it needs to go back into the soak till next class or it is cleaned enough to move to identification
and storage (dry off on paper towel first).
As you need water and counter space I always did my classes in chemistry class rooms. Art would do too. If you don't have counters and water supply in your room it is much harder. You will need 45 min to 1 hour for the cleaning portion of class. An experienced collector could d the same work in 10-15 minutes (examine, brush and change water) but a bunch of kids takes much longer with chatting, water, mess, etc.
Hope some of this helps.