I also have a 30-note Melodico whose rollers need fresh rubber and 
I would appreciate any hints.  This must be a common problem with
book-operated organs as well.

I had thought of buying some rubber tubing of the largest diameter that
would fit over the metal core of the rollers, but I haven't pursued
that.  It's probably possible to custom-cut a piece of rubber to glue
over the core, taking care to angle the cut so it is diagonal across
the surface.

All ideas gratefully received.

Mike Knudsen