I finally got around to forming a storage pocket for the radio hole in my FJ40. Started out by cutting a plug out of MDF, 3/16" smaller than the opening, in both directions. Cut out a piece of 1/16" ABS plastic using tin shears. Using a heat gun, I folded the ABS around the plug. Trimmed the excess material with the table router and slid the pocket into the radio hole. It's a tight enough fit to where no fasteners were required.