Auto body repair & detailing: window spots., calcium lime and rust remover, rubbing compound

Question
Well for the longest time I have tried to get rid of well there like water spots on the outsides of my windows.. I think someone told me it was acid rain but im not sure about all that. but I cannot find anything that can get rid of them completely. I actually tried some rubbing compound lightly on a corner of a side window and that only kinda helped.. any ideas?

Answer
This is one of those problems I have faced for years and nothing works specifically for the water spots.

Things I have tried in the past are:

CLR - Calcium, Lime and Rust remover.
Light compound with a machine.
0000 Steel wool with light compound or a real good polish.

Always try these things in a inconspicuous spot.