I use them every day.
First clean, do it traditionally, scrub with applicator hard.
Second clean, i don't bother with pure water, i use Mr Muscle window cleaner, (into my own trigger bottle) and spray a minimal amount onto the glass, then work it in.
It will pick up dust, so always make sure when you're cleaning to treat it like a squeegee, collecting the dust as you go along before finishing at the bottom of the pane.
The key thing is to use the least amount of Mr Muscle or pure water as possible. If you have too much on the glass, you're screwed.