Every substance has its own qualities, be it ABS or PVC plastics, Magic Sculpt or Alumilite, styrene or wood. If I need to remove a large mass of something that can’t simply be cut off with a mat knife or saw, I’ll reduce that mass with the large, coarse sanding drum on the Dremel. Sometimes I’ll use the 1″ upright belt sander in the garage. Usually that’s not needed, so I’ll start with the fine sanding drum. From there, I may go at it with the polishing brush bit, or I might switch to some medium-to-fine sandpaper (I prefer 220). More often than not I’ll go back and forth between paper and bits. When I’m satisfied, I’ll put a final polish on using some extremely fine sandpaper (so smooth it feels almost like normal paper). Some materials sand better than others. It’s just a matter of patience, really. For the record, I hate sanding. But it has to be done.