I used to have those clay dust footprints too. Then I got information (from
here? from Amoco?) about the dangers of clay dust. Now, before every
lesson I give them my little 2 minute speech about how the dust lingers in the
air for 4 hours, is cycled around the school, is breathed in, that whatever dust
is breathed in stays in the lungs forever, that they don't want to be like those
people at the mall with their tubes from nose to oxygen bottle.
And this has worked!!! Kids are careful and I never have footprints anymore!!!
The real problem is clay that falls on the floor, dries, gets stepped on and
turns into fine powder. So I remind them several times per class period to
"snowplow" the small bits of clay away from the edge of the table. We clean
up either by snowplowing the small dried bits into our waiting palm and then
toss into the trash can, or by sponging up the area with sponges that need to
be rinsed a few times.