The Dremel tool fix takes about 5 minutes per cylinder and is nearly idiot proof.
Using a 1/4" sanding drum.
Place the cylinder face down (Nipple cutouts up) on a solid surface with the nipples removed. Holding the Dremel tool parallel to the solid surface, place the rotating drum in the nipple cutout and make a single pass straight down until you reach the bottom of the cutout. Move to the next nipple cutout. The cylinder is massive enough that you can't go too far unless you really lean on it.
After this treatment the Thompson Center U-View pistol capper works wonderfully. It holds 100 caps.
Easy