>I teach a lesson (during the first project that involves glue) in k-5, every
>year (gets less involved in the upper grades) about how the Elmer's glue
>bottle works. I pull off the lid, show them the white plastic apparatus in
>the middle that clogs the hole (which, btw, I think should be a different
>color besides glue white, so the kids don't try to pick it out). I show them
>how to unclog the lid, and that I should NEVER see them stick anything in
>the hole or bite the hole, how changing the size of the hole ruins the whole
>thing. They seem to get it, and the glue lid lasts at least the year.