mybirdys2003 - Hi, I use nylon knee high's. (it actually started out as an accident as Schatzie habitually would toss her little tennis balls under furniture etc. In turn, she would scratch up our furniture trying to retrieve her balls out. So...I began placing the nylon knee high around the balls so she could just grab any part of the nylon when she hides her ball under the furniture and just pull it out herself. Well, It turned into a better toy for her as she figured not only can she hide her ball and get it out herself, but fling it, toss it, etc with it. She's quite a goofy character.
I hope your Yorkie enjoy's the nylon ball too!