At the weekend I played around with applying ink to watercolour paper and while wet scattering it with rocksalt. The rocksalt draws the ink to it and you get some interesting results.
This technique is easy - wet some watercolour paper using a paintbrush or aquapainter. Dip your brush into a small amount of ink and apply to the wet patch on the watercolour paper. Then sprinkle with rocksalt. Leave to dry and then brush off the salt.
I used Melon Mambo ink and these three cards were the end results of my efforts.