Don't waste money on expensive commercial glass cleaners when you can easily mix up excellent and highly effective glass cleaners at home for less. Next time your store-bought cleaner runs out, thoroughly rinse out the spray bottle and follow our recipe for windows that really need a good clean (as well as for mirrors, glass panels on furniture, and the like).
Combine 2 tablespoons ammonia, 1/2 cup rubbing alcohol and 1/4 teaspoon mild non-antibacterial dishwashing liquid. Using a funnel, pour the mixture into a rinsed, recycled spray bottle. Then spray it on windows, just as you would commercial glass cleaner, and wipe.