You can produce excellent window cleaning results with far less soap than you’d expect. in fact, pure water streaks are far less visible when they dry than streaks from a soapier solution. so, if you leave any water behind on a window after squeegeeing, it will look better using less soap. this is especially true when cleaning tinted or mirrored glass.
ofcourse the downside to less soap is squeegee drag, it’s more difficult to swirl, and wears squeegee rubber faster. it’s also harder to breakup bug juice and cooking grease etc… but, if you are cleaning glass on large high rise buildings, you don’t have to worry about that; your focus is on releasing the dirt from the glass and squeegeeing it off. and, straight water works in this example.
how do i know how much soap to use?
for all intensive purposes, i recommend trying… (drum roll please)…
the sea sponge test
most window cleaners don’t use sea sponges, but they are essential for high rise and interior office window cleaning, to wipe sills and squeegee rubber etc… the sea sponge test is this:
if you add too much soap to your bucket of water and dip your sea sponge into that solution; when you wring out that sponge, your hands and sponge will be a soapy – foamy mess!
what you want is, enough soap to breakup materials on glass, let squeegee glide and be able to wring your sponge without a soapy residue. you want just enough soap to hold the water to the glass, so little that virtually no bubbles are visible.
yes, it’s true, most people add too much soap to their water.
and sometimes, after squeegeeing, that can also cause a noticeable white cast on glass during a sunny day; the last thing you ever want to get into the habit is chamoising haze off glass so…
…experiment. try less soap. you know the saying:
“less is more”!