in his recent book on early medieval sword blades, Dr Stefan Mäder published a number of period depictions of sword polishers at work. Their tools seem to have remained pretty much the same for centuries.
The earliest depiction is from the 9th century Utrecht Psalter, the most recent is 17th century.
Polishers used a specific bench with an additional beam mounted lenghtwise on top, like a miniature bridge. The sword would be fixed onto the beam. Because blades were often longer than an arm's reach, two polishers would work at once from either end, each polishing his half of the blade, probably with an over-lap into their fellow's half. This would provide a seamless polish.
The actual polishing tool consisted of two bows, similar in shape and size to a modern coat hanger. They were held with both hands at their ends in such a manner that they formed an elipse. The two bows embraced the bridge beam and the sword. The polishing pad was fixed to the end of a small peg which was inserted through the center of the top bow. Exactly where a coat hangers hook would be, only on the bottom side.
A little horn fixed to either side of the bench would contain the polishing paste for each polisher.
The design of these polishing bows allows for a multitude of angles for the polishing pad. To polish fullers would have been no problem. While polishing, the low bow would slide along the bottom side of the beam which would provide consistency and stability as the polishers push forward and pull back.
There is at least one image online:Browse to folio 49 recto, see the miniature at bottom left.
This 14th c depiction from the Romance of Alexander shows a straight top stick instead of a bow. But the polishing device inserted into the stick's center is clearly visible. Note the flutes on the bottom side of the lower bow. They may fit into some kind of bearing that is obscured by the beam.