Green Crud On Buffalo Nickels

My Verdi-Care treatments on copper didn't work too well. I was never able to rid the deposits.

Acetone and Verdi-Care should do the trick.

I'd suggest just trying Acetone. Possibly a small brush in the Acetone on those might help. Not much to loose. Remember to not use the Acetone over and over. Use new stuff each time. As to how, Whitman and all Folders are made using a glue to glue done the slotted cardboard onto a piece of paper. Not a high quality method. Usually much of the glue is on the slots where the rear of the coins are. In moist areas, this glue gets activated and attacks the rear of coins. going from Whitman to Dansco may not be to smart since possibly same problem. Is the empty have a shine to it. If so, that is the glue so you may end up getting the same results.
Although more expensive, this is why so many change to Albums.

I would add that the OP should keep in mind that significantly extended immersion times in olive oil are capable of creating an acidic environment likely to cause mild etching depending upon the nature of the substrate and pH measurement.

Once I had a severe problem higher grade coin and kept it soaked in olive oil for over a week only to find that the patina had been damaged with obvious etching.

I never tried this but testing the olive oil periodically with pH test strips could be a method to avoid costly mistakes from significantly lowered pH values...

Thank you everyone for all your help on my problem. I will try all of them once I replace the crud nickels with newer ones.

Craig

Well, that's a shame.

As a kid I kept a Jefferson nickel collection in a "Treasury of Coins" album which consisted of several heavy cards. The labeled coin holes were backed with clear plastic. The cards fit into a sturdy cardboard sleeve with photos and printed information about the series. I thought it was a nice-looking album, more professional-looking than the basic Whitman folder. After years of storage on a bookshelf I discovered the backs of most of the coins had the same green corrosion you show on that Buffalo. The metal was deeply pitted in places and the coins were ruined. No great financial loss since all the coins were circulated pieces pulled from circulation. It was however very disappointing to learn that the "nice" album I selected to display and preserve my collection turned out to be not such a good choice.