Like Jon said, sulfuric acid should do the job nicely. The use of sulfuric acid in the bleach of Ilfochrome chemistry is one of the reasons why the emulsion is coated on Melinex polyester and not paper!
Concentrated sulfuric will char paper as if it had been in a fire. If you want to do this with sulfuric acid, you need to used diluted sulfuric, say 50% or weaker. Be aware of the hazards of making dilutions of sulfuric acid - look them up if you are not familiar with them.