In MMD 12.02.05 Charles Davis wrote:

> I believe that sanding while the roll rewinds runs the risk of
> getting sanding grit, paper dust, etc. caught up within the roll
> as well as possibly going into the tracker bar by way of the vacuum.

Charles, thanks for your observations.  I did suggest that this should
only be attempted on an expendable roll.  Since there is no suction
present at the tracker bar during rewind, there is no danger of
anything getting sucked further into the stack.

A probably unnecessary precaution would be to place a blank piece
of paper between the tracker bar and the rewinding roll during this
process so that even dust particles that might land inside the tracker
bar holes would not go further during the next play of a roll.  And if
noticeable dust is being produced, too much force is being used.  The
object is to create a roughness to the paper surface, not remove
material.

Since suggesting this, I did try a "static" test, i.e., simply sanding
lightly by hand but not on a moving roll.  No observable dust was
produced.

John Grant