And FWIW Flex-hones says always use oil with their products as lubricant. I keep my main go-to in a motor oil bottle so it's constant-bathed and ready. If the flex-hone can't do the job then you need to up the ante and use an actual blade-type adjustable reamer (also with oil), but for general clean-out/clean-up good to at least start with this hone, and follow Chas' excellent pointers.