Glass polish

Anyone tried these scratch removal and polishing kits?Going to have all the glass out while the cars away for a respray so id quite like to do all the windows clean up all the little scratches and polish all the glass etc. Is it quite tough or does it remove scratches with ease?And is it messy and take ages?
Cheers
Jamie

what kit is it? I haven't tried any but would like to, especially for my windscreen as its so scratched especially when bright sun on it. Let me know how it goes.

I was going to go for the light or medium  kit as none of the scratshes are deep,just scuffs from the wiper and scraper seals.Prob buy it next month an see how it goes,ive heard they work wonders but are messy work ,ill put pics up aswell as im gonna start a build thread soon.
Cheers