1) Clean windows on a cloudy day or evenings
On a sunny day, water or cleaning solution dries quickly leaving the windows with streaks or spots.
2) Use newspapers or lint-free rags
This will prevent lint or fibre from sticking on the freshly polished windows.
Paper towel, cloth rags are the worst culprits of lint.
3) Wet the glass
To remove paint specks on the glass, wet the glass. Load a new blade on the razor and scrap off.
To remove droppings, wet the glass and scrub off with a nylon scrub pad. Test the nylon scrub pad on a small inconspicuous area to ensure you are not scratching the glass before going full force.
To remove labels and stickers, wet the paper labels with lighter fluid or nail polish remover then lift them off with a penknife or pocket knife.
4) Use a blackboard or whiteboard eraser
Rub off streaks on the glass windows with black or whiteboard erasers.
5) Best cleaning solution
1 part water
1 part vinegar
If the smell of vinegar puts you off, you can substitute with ammonia
Dish washing liquid make excellent cleaners. A note here, go easy on the dish washing liquid, a few drops with lot of water goes a long way. The less suds in the water, the better as this will prevent streaky residue.