Ground Glass - Urban Legend? 
In 1977 the ChapStick company was indicted on the charge of including ground glass in several of their lip-balm products.

This looks exactly like an urban legend mention in the Lip_balm article:

There are some urban legends stating that lip balm manufacturers add special chemicals or even fiberglass to their product to facilitate lip chapping, but none of these claims have ever been proven.

I suggest we remove it, unless some credible evidence is provided.