Can you explain the cleaning process in more detale?
I very afraid it will be very hard task for me with my english

In addition binocular, I have some wax carver like this:
http://www.widgetsupply.com/dental-picks/carver-sets/SAC4-12PC.jpgI put coin in water about 10-15 min. After this time metal oxide become lax and easy cleaning off by metal wax carver.
After clean small area of coin you need dip it in water again in order to wash off results of you work.
Attention! Wax carver must have NOT sharp edges!!!
Really, if You look in binocular even if one time - You will understand how easy separate oxides and good metal with help it. Very important advantage of this method - saving (retention?) of patina.