A few questions

[geoff]

In message , Rick Hughes writes

>>> I need a real good UPVC window cleaner. Both inside and out the white

[The Natural Philosopher]

then underlay and carpet? yes

Would this help to retain the heat?

No.

[Peter Johnson]

Sandtex PVC-U Cleaner, comes in 1 litre spray bottles. On the bottle it says that it removes mould and grime and kills germs. I got mine from a Crown Decorator Centre. My frames weren't that bad but when I worked at a CDC we sold a lot to a contractor working on a building that faced north and who said it was effective on badly discoloured frames.