Is this bronze disease?

I just bought a Nero billon tetradrachm, and on the rim it had dark green specks that could be picked off with a fingernail. The dots were so small you couldn't see them on a photo. I picked them off and put a coat of renaissance wax on it. Does this make it safe, or should I treat it?

Some of the specks were powdery but looked more like corrosion or verdigris to me