What does this have to do with cleaning guns? Plenty. Bad mopping involves swirling a mop in a bucket, wiping it around the floor, then dipping it right back into the bucket. All that grime you just picked up from the floor went right back in the clean water so it can be redistributed elsewhere on the next swirl. Doing it right, and actually getting a floor clean, requires wringing the dirty water out into an empty bucket, so the clean mop water stays relatively clean. With this common-sense method, you’re actually removing the dirt from the floor, not just moving it around.