~ this is the glass cleaner I use on a regular basis. the key factors for me are using a clean terry cloth towel (washed with no fabric softener or dryer sheets). also a couple other factors in assure the end result are; cleaning the glass out of the direct sunlight, cool glass, when wiping clean the glass... wipe up and down, side to side and around the perimeter. when you think they are clean... keep wiping. that should help with a positive end result.