I agree with using the school glue, but I sew over pins all the time. I try to take them out, but there is always one I didn't see in there somewhere. I put the pins in so that only the point is in the seam allowance, but once in a while I have sewn right through the middle of a pin and it came out bent in half. Didn't seem to hurt my machine any. I don't remember doing that with my computerized Bernina, though. That's good. I'll try not to.