Just playin'

Take some very old Ilford Warmtone paper, print a negative, develop and fix as normal.  Then, bleach back fully in cupric sulphate bleach (takes a while to get going, but once it starts it motors along nicely) and finally dunk in hot lith developer.  You might get something like this:

I quite like it.  It has an old, rather soft look. For the right negative I think it could be an interesting diversion from the norm.