I've also found that they seem unnecessary, a damp paper towel work just about as well.

I thought paper towel or tissue was fine for cleaning whiteboard until I tried this eraser..

sometimes a paper towel works better for tougher cleans but does the trick most of the time

I went back to using the classroom's paper towels because they worked much better than these for cleaning

A paper towel is more effective

I cleaned with water, but it was back to being dark, and almost as worse as before I washed it.

Worked exactly as you would expect