How can I make a better whiteboard cleaning solution? I just started work as a lab assistant in a chem lab. The whiteboard the instructor uses for classes gets very dirty very quickly. The woman who started at the same time as I did spent over 3 hours scrubbing it with a solution of a powdered soap-like product in a milk-carton style container to get it anything like clean.

I'd rather not watch her do that again (or, worse, do it myself). Can I make a better cleaning agent without using too much of an expensive chemical?

So far  I've seen large quantities of Ethanol, Acetone, Alcohol, and milliQ water. What else we may have, you folks would probably know better than I.
Andselisk's recommendations are great, but you'll save yourself a lot of trouble if you just throw all the erasers out. They get crud on them quickly and after a while, they put more back on the board than they wipe off.

A microfiber cloth is much more effective, and works for a shockingly long time. I would bet on a filthy cloth over a brand new eraser, and unlike erasers, they can be thrown in the wash. You can get them specifically for whiteboards or just stop by an auto parts store.