LuckyLefty's question about where to get a thumb slug puller (remover) caused me to ask: "What good does either a thumb slug or a thumb insert do?" I have thumb inserts in all of my balls and when I started using Ron's Magic Carpets, I had to open up the thumb hole so my thumb would fit with the Magic Carpet in the hole. If one drilled the thumb hole in the ball and used the Magic Carpet, how would it be different by using a thumb insert or slug? Obviously, if you opened up the thumb hole too much it would be easier and cheaper to replace the thumb insert or slug instead of plugging and redrilling the thumb hole. My next new ball will not have a thumb insert as I fail to see an advantage. Am I missing something?

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What's with the Braille on a drive-up-ATM?
Never under any circumstances take a sleeping pill and a laxative on the same night.

i use the slugs and that is because i found without them that the resin balls with a thicker coverstock become quite tacky and impossible to clear cleanly time after time

Yep, it was the reactive resin ball that made thumb slugs so popular.  When reactives first came out, bowlers started finding out that they would hang up in the bare thumbhole of a reactive resin ball, especially if their thumb was in the least bit damp.  Urethane slugs give you a cleaner release, plus you can get a more consistent feel from ball to ball.  Vinyl slugs and thumb inserts, however, can also give sticking problems if your thumb is damp.  So, a lot of bowlers jumped on the urethane slug bandwagon.

One good thing about using a urethane slug is that if something should happen and you don't like the fit, the slug can quickly be drilled out and replaced in a matter of minutes, rather than waiting 24 hours for plug epoxy to cure out.