yes i know what methods/cleaner they use,to be fair neat tfr would clean most things,they use disposable gloves by the look of it,so suggests they are using"monster cleaner"(the trade name and code number escapes me the mo but i'll find it out) used this stuff when i was fitting windows-it cleaned everything and anything-just found the place who bottles all this up for companies to sell on , will post the website address if there is anough intrest(seperate post please)this stuff will clean even the worse window frame you can imagine