I've shared photos of my little "experiment" to give you an idea of the possibilities with this tool.
Felt 60 Grit Sandpaper - two pieces back to back
Scrungie Pad Netting - multiple layers
Lace Tissue Paper
Each of these samples are 2 inch square pieces of 20 gauge annealed copper. The impression material was sandwiched between two pieces of metal and run through a manual rolling mill. I found getting the right amount of tension on the rollers to be the biggest challenge. I used the method demonstrated on a Rio Grande video.
First I would open the rollers wide enough to slide my sandwich between them and then turn the wheel on the top until it was snug (hand tight). After making note of the setting on the dial, I would open up the rollers and remove the sandwich. Then I would crank the rollers back down to the noted setting and then close them another 10 points. This method seemed to work better on materials that had low compression factors, like the lace and the sandpaper. On items that were thicker, yet soft and compressible (like the scrungie and the tissue paper), there was not enough pressure at the 10+ setting to make an impression and I cranked the rollers at least another 10 or 20 points. I have a few more annealed squares and I few more items that I want to try, so I will continue this post later. If you have anything that you want me to try and report back on, let me know.