Is it possible that if you try to use a string that is very oily that it can do something to your grommets so if you try to string with a better Gut string that it will slide around and fray apart and break on you? I seem to be experiencing that with one of my racquets. If this is what is happening, I am not sure how to correct this other then buy new grommets or maybe string with some non-gut for awhile and hope it cleans them out. Ive actually usually had very good luck with Global Gut in the past, but I think I have finally found a batch that is not worthwhile. I had one premature breakage, and then on the second try (I strung with expensive stuff in between), when I got to the last main it sliped right out of my fixed clamp when I was going to tie the mains off. I suppose it's a good time to clean all of my clamps as well.