[notout86]

Purely for WASHING I use plenty of Armorall car wash mixed with rain water ( not our mains tap water ) in an oil drain pan.

I squirt off grit first with the hose. Then I dip a broom with dense soft plastic bristles in the pan and LIGHTLY paint with the tips of the bristles and plenty of wash all over in one (front to back) direction using one stroke only. If the wash does not wet well enough to form a continuous film I add more Armorall. Each time I dip the broom in I agitate it to let dirt drop out to the bottom of the pan.
Then I squirt off before it dries.

I tip out the original wash and squirt out any dirt.

Then I repeat with fresh Armorall/rain-water, but this time I go back and forth LIGHTLY with the broom ( one direction front to back ) then squirt off the wash thoroughly before it dries, repeating the broom if I see any missed dirt and squirt that area off. The idea is to let only the tips of the bristles do the work and do not press the bristles flat so no dirt gets dragged.

Finally I throw rainwater over the lot and lightly pull a towel (one direction) over it to dry. If the towel starts to leave a bit of water-film behind, flip over, or use another. This method TRULY leaves the paint water-spotless. The only rubbing I do is on the glass but not the lights.

If the rainwater shows a lack of beading then I might apply polish/wax, but that's another story.