"As an Optometrist, I recommend washing under water to remove large particles or debri. Then we use eyeglass specific cleaner, which is almost diluted dawn dish soap, water, and some rubbing alcohol. I agree, no paper towels. Microfiber cleaning cloths for glasses are best or a clean cotton cloth. Doing this once or twice per day should take care of it. Also matters what type of lenses you have and if you have any anti-reflective treatments on the lenses which should help cleaning and resist smudging/dirt in general. "