Just picked up a new customer and done a first clean for him yesterday, he has got upvc frames with vents on the top that stick out about 2cm, all the windows are leaded, they all cleaned up nice except 2 of them, one that's is on the 3rd floor and his living room window. The 3rd floor window has massive streaks either side of the vent running down the window from the first line of lead, I scrubbed for abot 10/15 mins and it never even touched it, sprayed some viro sol on and scrubbed again and still nothing. I can't get up close to the window because my ladder ain't long enough. The living room window is different, it has stains running down after the last line of lead. I scraped it and scrubbed it but it won't shift. I have a couple of other customers who have hard water marks and I've used viokal and also tried lemon juice then scrub with a bicarb and vinegar paste but it has little effect. Anyone used something that actually will shift this?