I do use tap water in my Kärcher which has a squeegee but my reply was to the OP when he asked if he could just use a hosepipe to "eliminate soapy water sud-streaks".
What about buying filtered water? Is this suitable? Sentinel X400 Sludge Remover 1L (toolstation.com) High performance cleaner, specifically designed for cleaning older central heating systems. A non-acid treatment which restores circulation to radiators and pipework. Ruthlessly efficient formula shifts built-up magnetite sludge, eliminating cold spots in radiators and restoring proper heat distribution.
What are you on about? This is the first time that i have heard that tap-water causes streaks!! . I have NEVER washed upstairs windows with a telescopic extension other than 2 days ago.
He uses half vinegar and half tap-water. 2m19s He sprays it on window then just wipes off with one micro-fibre cloth and then another micro-fibre cloth, removing solution, simple and apparently the best way to do it.
The problem is how do i spray the top floor windows with vinegar/water? I think jet-sprays are only made to attach to house-taps.
Mix 50% water with 50% vinegar, fill a water -pistol with solution then use a step ladder to get a good squirt of upstairs windows. Use cloth 1 to wipe solution away then second cloth to smooth it/dry it all out.
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