Pull the hardware, and tape over the pickups (unless you want them dull as well) Testors makes a Dull Cote spray. I have never used it on a guitar, but on models this stuff is amazing. It is clear, but will remove the gloss. You might want to try a bit on the back side to see if it will bond with your existing finish. You may still need to scuff it with OOOO steel wool.