Don't need to. I just use my common sense instead. Think about it for a moment. Eraser and paper. How tough is paper? Is there a need for abrasive? No. End of story.
Been a while since I used an eraser, but there definitely were some pencials in grade school where you bought something like 50 for 99 cents that had the most terrible erasers on them the world ever saw. They would do nothing but smear the pencil and, yes, tear the paper.
I have no idea what they would do to a phone. Probably nothing. Just thought I would mention my experiences.