Transparent acetate sheets can be used to make greeting cards. They can be folded or cut to the right size with a knife or with a pair of scissors. They can also be used to make shaker cards or they can be painted with glass paint.
Simply stamp your design onto the plastic using a permanent ink (such as Stazon) and then cut to your desired shape. (Quick tip; If you want to hang your design remember to punch a hole before you start shrinking). Then use a heat gun to warm the plastic and it will shrink down about 7 times smaller. As it shrinks it will twist and curl but should return to its flat shape once it is fully shrunk.