Congrats on the coppers, fun to find! The first thing you can try is the old paper and side of a pencil rubbing technique, you might be able to pull some details that are readable.
Google King George copper first to see what examples look like so you can compare the obverse and reverse of the coin. Coppers usually are warn and hard to read, it's the nature of the material (copper) and age; if you use electrolysis you will ruin the coin - however, there's not much value in them if they are unreadable, the process would (could) possibly reveal better details.
Personally, I like them green and untouched, just adds to the allure of what they are - regardless if you can read them, clearly you on to a site that may have more!
