As I was casting about for a technique for an embossing enamel swap, my friend Carol reminded me of the following: scrunch up some heavy-duty aluminum foil. Carefully unfold and brayer. Color with alcohol inks and let dry. Cover evenly with Versmark and clear, thick embossing powder (I used Franklin Opals). Heat until set.
I used it for the background on this ATC, for a swap, and with one extra I made this card as a thank you for a friend.