Does anyone know what was the solvent base for Pharmacist Formula head cement?

I have an ancient bottle that did finally solidify and would like to redissolve it. It sort of smells like methyl-ethyl-ketone, but I am uncertain if that is the solvent, and it seems somewhat unlikely as the stuff really did not evaporate from the bottle rapidly like an MEK based head cement.

Google did not find any definitive answers.

I have just recently pulled out my boxes of tying materials and am getting set up once again (after ~25 years). So I can say all the new materials are a bit overwhelming...

Thanks