I have used this technique for posts of my cards made with the sets Classic Convertibles and In the Wild. It is a technique I learned from a technique junkies newsletter I subscribe to from the site
www.patstamps.com. If you are a subscriber you get pics as well as text directions (tell them Britta Ward sent ya!

)
Basically, you stamp an image and cut it out to fit in a bottlecap that has the rubber ring removed. It can be new or used. If you want it colored, do so before you put it in the bottlecap. Place clear embossing powder in the cap to completely cover the bottom image and then some. I place mine in an oven since the embossing gun would blow it around. At 325 it usually takes about 4 minutes, or I do it while Sculpey clay is baking. Take out and let cool, then use it in your card.