I cleaned a new customer windows this morning, which hasn't been cleaned for well over a year. Trouble is I am finding gardiner brushes for really dirty windows are not tough enough for getting those stubborn marks off the windows. (I even used ubik on the brush today) Now I am not slagging off gardiner brushes, I do think they do reallygood light brushes which make life so much easier for us guys who use wfp all day but when I was cleaning the ground floor windows, i could see marks that wouldn't come off it. I had to use my finger nail to scratch a few of those marks off instead, I just knew there would be stubbon marks at the upstair windows seeing how bad the downstar windows was. I've pretty much given up using ladder now, can't be **** with it. Whenever I used to get new work I alway use sure i trad it for the 1st clean, then wfp for the second. From now on i want to be able to use wfp for the 1st clean but i need to find a strong brush that get those bad ass marks off without scratching the windows I have not use vikan brushes before, are vikan the toughest brushes you can get to use on glass.