Adding Metal Covers To Humbuckers?

[j. pierce]

How does potting figure in when adding a metal cover to a humbucker - assuming the pickup was already potted to begin with, and I solder the cover on - should I pot the pickup again to fill any space between the coils and the new cover?

I've potted some cheap pickups before, and they were covered, but I assume they weren't ever potted to begin with. If I start with a potted pickup and add a cover, would I be okay?

[crafty]

Apply a thin bead of silicone to the top of the slug coil and that should stop any microphonics from the cover. If you ever want to take the cover off, the silicone just peels off quite nicely.