So, I grab my bag of really tiny felted wool scraps left over from my shrunken sweaters from diaper cover making.
I folded them in half and used the sewing machine to sew each of them in half. They barely made it under the machine foot, but they made it.
I wanted to make the non-sewed edge side the nice cleaning edge of my eraser, so I lined them all up with sewn edges next to each other. Then I took a needle and thread and started sewing in a serpentine fashion to catch all of them and try to keep then next to each other. It did curve up a bit on the edges, but I was ok with that. It was so thick that I had to make the needle go through only the first half in order to catch my needle to get it through the next half.