I have been printing a lot of images on 2x3 Zink paper recently. I remember from
years ago when the Polaroid POGO first came out there was a video about how to
distress/alter the Zink prints. I decided to give it a go. I used household ammonia.
I used an eyedropper to put a few drops on the paper then spread it around with my
finger. The ammonia begins to eat through the top layer. You can sort of control the
destruction by running water on the photo. Be careful - the force of the water could
wash off more than you meant. You can also just dab the photo with a paper towel to
mop off the extra ammonia. I let the photos dry over night and then spray with
acrylic spray. Sometimes I use kamar varnish spray which is a little more glossy.