A while ago I experimented with printing from paper negatives "wet" - so once I'd developed fixed and washed the negative, I sandwiched it with the paper from which the positive was to be made immediately.
This produced some interesting bubbly smeary uneven effects.
Giving paper a brief bath in fixer after exposure but before developing produces some interesting effects too (this was discovered, ahem, inadvertently)
I imagine that by combining the two things - not washing the paper negative properly after fixing, if at all - you might make something groovy happen.
As (I assume) you are starting with film, you could print a positive, make a (contact) paper negative from that and print from that. the extra generations will introduce tonal and contrast distortions, as well as throwing any or all of the above ideas I suggested into the pot.