The other option is to re-clock the bottom cup. By removing the cup and turning it slightly before reinstalling it, you “misalign” any pits in the cups. Unfortunately, this takes more tools - you need a bearing cup remover and a bearing press. You can use an old screwdriver to remove the cup, but alignment is critical to reinstall. You can do it with all thread, bolts and blocks, but you have to be very careful to avoid damaging the head tube.