I use them for 2 things, shaker cards and the tissue & acetate technique. To learn how to do these techniques, click on "resources" at the top of the homepage and there's a tutorial on each of them. There are probably many other uses for acetate sheets too, but these are the ones I'm familiar with. Also, I buy my sheets at walmart or at staples (an office supply store) as they are so much cheaper there than thru SU. HTH
stampingnut