Best way to polish a humbucker bobbin

[hamerfan]

… without a polishing compound. I don‘t want to have white residue in the holes.

I am about to buy a used TB-5 with badly treated surface.

 

[ICTGoober]

A toothbrush and a soft cloth.

 

[akio]

If it's really bad you may need unscrew/push out the pole pieces and wet sand them with Micro-Mesh finishing pads, going in series from coarsest to finest. I had to do this on a my double creme '59 that got discolored by a pickup cover.

 

[Drak]

Abralon flexible sanding pad on an orbital sander.
I've done it, on pickups. You can make them look like new again.
They go from 360 to 4000, and depending on how bad its whacked, you'll have to step yourself through each grit just exactly like you were micromeshing a finish.
360, 500, 1000, 2000, 4000.00.
You could probably stop at 2000 and be OK wid it.
It helps to have compressed air around if you have it, but not critical.

You may want to remove the pole pieces (or not), that's up to you.
I did with mine, and gave them an individual polish-up before re-install.