What to fill in guitar cavities with to paint over

[thetulipcutter]

I have an Ibanez S that I sanded long ago and have been wanting to paint it. Recently I have been thinking that I want it to be just a single pickup guitar and no volume or tone knobs showing. Does anyone have any suggestions for what to fill up the pickup cavities and switch and pot holes with so that I can paint over them without worrying too much about them sinking in later?

[bulldogguitars]

When Ive done this Ive cut a piece of wood as close as I can to the original shape and glue it in the hole. Then I will fill the gap around the wood with Bondo, let dry and sand. You may have to due more than one application of bondo. When you fill it be sure to leave it a little higher than body.

[Mystic]

This may sound like a dumb idea but it works great on wooden furniture to fill nail holes. Drywall compound.