I have used the slightly rough nail boards to erase mistakes, believe it or not. Then I smooth it with the very fine boards. I use the rough for the edges like suggested.
I have also used a white eraser and ink eraser at times depending on the card finish.
I would have some rough, not so rough and slightly smooth. The small size helps with corrections. :oops:

I am not real neat sometimes. LOL These have worked for me.
HTH,
Shirley