A couple of months! Hell Stuart, a week at most I would say.
A full boil wash before use, and if an individual scrim, after a days work being used as a wet scrim for sills, frames and so on, as against buffing up glass, then maybe another days use after its second wash and it should be spot on.
There is of course microfibre cloths too, I haven't really used them, so I don't know how quickly they break in. The one I do have is very good, but its only one of the small ones, doesn't last very long because it isn't big enough.
Haven't bothered with getting more as I use WFP, so scrims and microfibre only used on insides and the odd window outside now.
Ian
