Remus had an inexplicable hate towards pencil erasers. True he liked to work with pencils but he hated it when he made a mistake because that meant he would have to use an eraser to rub it off. And he really hated using erasers.

So normally he would be content in just using pens or quills and would be real careful with his work minimizing any chances of mistake.

Just so he didn't have to touch that dirty piece of rubber.