OK, I'll confess I'm a bit of a thrifty saver. No scrap of card stock gets tossed. And I'm strict about that, especially if it is the lovely SU! white card stock. I save my scraps of white for a few years in a big crock. Then, when it is full, I go on a paper-cast ornament frenzy.
This year, friends Leona and Donna came over so I could teach them. The method is that you must reduce the white scraps to paper pulp by first soaking them over night, then pureeing them in the blender with a few cups of water.
You then strain the pulp and press the soggy pulp into molds. (Be sure to spray the mold with a mold release first.) Use a sponge and towels to 'press' out as much water as possible and to push the pulp into every detailed nook and cranny of the mold.
Most of my molds are reproductions of antique German woodcuts. They come from House on the Hill in Elmhurst, Il and are really designed for cookie making. I also have some clay molds from Arnold Grummer, but they don't have the old world detail and charm, although they do dry faster and un-mold much easier.
It is really hard to photograph the detail in white-on-white. Hopefully these photos give you some idea of how marvelous these are.