So, this happened at a customer's the other day.
I arrive and clean.  On arrival, the door doesn't stand out as unusual (but I didn't look terribly closely).  A couple of hours after the clean, the customer (terrific customer, has recommended me to six other people) calls, upset that her door has "streaks all over it".  When I went back to look, I have to say that I think I'd have noticed it as I walked up to the house.  I didn't notice at the end of the clean because when it's wet, it looks OK.
The picture below is what I found.  It's not streaks on it, it's as though the colour's disappeared from the UPVC.  The surface sheen seems to be missing on the white bits.
Customer is as staright as a customer could be and she says no decorating work or anything done (and, as I've said, it seems to be an absence of colour rather than something spilled on it).
I have an idea what it might be but I'm not going to prejudice views, so have any of you come across it and was there a way to resolve it?  Strangely, a day or two later, I saw another brown door looking very similar elsewhere.
Vin
