I have made several cup and saucer pin cushions and always used the steel wool from the hardware store. That way, I don't have the 'blue soap' falling off off all over. I use a small styrofoam ball and then cover that with steel wool. Over that I put some soft batting and then my fabric. By the time I get all finished with this it is pretty fat. I gather the fabric circle like a yo-yo and pull it tight and seems to hold everything together. Then glue into the top of tea cup. This is a good use for cups that are too cracked to drink from but still too pretty to toss out.