Hi ILoveCows,<br /> Thank you for purchasing our packaged batting. We don't recommend using our cotton battings (or any other cotton battings on the market), since most of them do contain a "scrim" binder, which enables quilting stitches to be spaced further apart. That "scrim" (think of a cobweb), is synthetic. Even though it's 'barely there' it might cause issues in the microwave. We recommend our "Wrap N Zap, which has no scrim and is suitable for microwave use. When you use it, make sure your fabrics are 100% cotton (& prewash them). Cotton thread is also advised. You can see more info on our site (pellonprojects.com) as well as downloading free projects. We also recommend micro-waving at only 2- minute intervals. 5 minutes in 'micro-wave time' is actually quite a long time. I hope you will give Wrap-N-Zap a try, and thank you for the opportunity to respond!