The actual way is to use dish soap under running warm water (not hot apparently, it can damage some coatings I’ve learned in this thread). First rinse the lenses under a stream without touching them, to wash away any loose debris (which is the reason why you should never use any sort of cloth to wipe them, they just move the debris around which causes scratches). Then use a bit of dish soap on your (clean) fingers to gently rub each lens, which will get rid of any grease or other smears. Then a final rinse – for this one it’s best if you use a very slow and even stream as it gives you the fewest water spots, but as long as you don’t have super hard water it’ll be moot in a few minutes.