They are simply bits of the eraser that have been rubbed off from the friction against the paper.
One of my teachers years ago used to call them "pencil poopies".
Rob, they are called erasures.
I tried it many times, it does not come off all the way, but most of it comes off.
lick it
Yes, the ink from whiteboard markers (or dry erasemarkers) will not be absorbed by the plexiglass.
If you've already tried washing it with soap and water, then try an eraser. Regular kind or the Mister Clean Eraser thingy.
Yes
Smaller rocks.
It wears down the high bits (and the bits that come off fills up the low bits).
I tried it many times, it does not come off all the way, but most of it comes off.
no but you will lose brain cells
By the water scraping along it so often that little bits come off.
lick it
there is no key to turn it off
Use a soapy eraser.
Take a pair of scissors and using the tip of one end of one of the blades, slice around the metal that holds the eraser, and then pull out the eraser. bite it off wit your teeth butt not to much grip
you touch the eraser button
Anything that isn't smooth Just as long as bits don't come off in case they digest it
try with an eraser i tried eraser on my desk with a white desk and blue marker and theres such a little stain that u have to squint ur eyes too see it