I always prewash my fabrics and use the bobbins as top thread when zig-zagging the edges of my fabric before washing. Great way to use up all my bobbin thread. Also, use bobbin thread when piecing. I always put the bobbin on the up right spool pin with a felt pad underneath to keep the bobbin from spinning out of control. I make the circle felt pads out of left over batting and cut a small hole in the center (not perfect but they work).