0000 steel wool works really good. Just cover the pickups so that they don't attract the steel wool dust. I usually put some masking tape over the pickups before I do this. I detack the tape slightly by first applying it to my jeans so it won't do any damage to the finish. You won't need to rub hard with the steel wool, and it's not too abrasive to damage or scratch the inlays. Just work in the direction of the grain as to avoid any visible scratches - a little harder near the 2nd octave where you really want to go the direction of the frets. Best method I found is to use a little oil with the wool to wet sand which will minimize any scratches but really pick up the dirt.
Kris