I second that - the sanding block is the way to go. Oh, I've been told by a couple of people [they must be real artists because they work at an art store

] that you can unravel it and tear and rewrap it. For get it. Just sand it down.

I will suggest - and I've never seen your work, but when blending, get a nice plate finish paper or illustration board. Avoid grainy or textured papers.

I used to do medical anatomical illustration in graphite with blending stumps. Plate finish illustration board all the way and a variety or stumps.

Pete