Overspray
 

Hi was just wondering is an sos pad with soap+water or window cleaner ok to remove a bit of overspray on the window ?

Use a Single Edge Razor Blade angled sharply to remove what I assume you mean paint overspray. SOS pad might scratch the glass.

Clay bar.

+1

Works amazingly well. I had some kind of overspray after I had a wreck repair done and the clay took it right off. I think it was the clear coat because was hazy, no color.

is the Meguiar's Smooth Surface Clay good enough ? or Mothers Clay Bar System ?

Either one is good. No need to spend more on it.

0000 Steel Wool dry also works well on glass as well as polished stainless.

depending on how bad it is, i'd probably start with clay, then QD and razor blade.

last would be abrasives like polish.