I see that Karen (kttyhwk4) has given you a great answer - there are two types of WSS - the one that looks like plastic is called a topping - therefore you use it on top of your item that you are embroidering. *4U, Shirlene
I put a med tear away on the back and wss on top and remove the wss using water and a Q-tip after I've trimmed it. One sheet of each should do the job. You may want to use the same thread colors on the back .