Bettagurl, don't know if they still do, but the glosticks made 10 years ago had a glass tube inside with some of the chemicals inside to keep them from mixing until you snapped the glass tube. Be careful not to get any glass in your mouth or cut yourself.
I have PROOF that biting your nails is bad for your teeth. Over 20 years ago, I was in a car accident that caused me some broken teeth which were repaired with bonding (like caps, but not as durable, cause less damage to the teeth). Last night I was biting my nails and lost a big chunk off one of my front teeth. Can't stop sticking my tongue in the gap. Was able to get a dentist appointment at a convenient time, but not until Monday.