http://www.cleancomputes.com/Cub/Super%20A%20-%20Super%20AV/TC-39B%20Parts%20Catalog/Page%20118.jpg
The photo below shows my old one, and it is possibly a VERY thin strip of leather, but it could be some kind of paper. The upper piece shows the small rectangular depression where the hole for the brush was.

If it is only for keeping out dust, seems like I could use almost anything. If it is to insulate the brushes from possible contact with the band, could I use rubber, or plastic, or electrical tape? Thanks for your info and suggestions.
Dale F