Cleaning Copper!!

VERDI-GONE™ will remove verdigris:

https://goccf.com/t/33105

Take a turket baster and go to most autos. Lift the hood, take the caps off the battery, use the baster to remove some of the acid and put in a glass jar. Now place your green coins in there and allow to stay there for several days. If the water turns blue, you now have Copper Sulfate and you can use it to kill the grass growing in cracks in the sidewalk.
For real since those are not expensive coins, try all the non expensive methods first. Soak the coins in plain old distilled water. If nothing happens after a few days, try gently heating the water. You may also want to just try some of the things many people try with normal household items. You could try dipping or soaking them in Olive Oil, Lemon Juice, Tomato Juice, any jewlery cleaners, etc. Just remember that most of these, if they work, will make the coins be considered cleaned but since you said they have no numismatic value, nothing to loose by experimenting. Just don't go out and purchase something when there is no need for it. Even to go our and purchase items like Acetone, etc. and no other usage for that is just wasting money that could be spent buying coins.