I hope Soda drinkers, particularly the fans of Coke don't get offended but this is how I use this sort of beverage: We were served food at the workplace a few weeks ago and of course Soda is a must(!) for these people. One large bottle was left, more than half gone, after the party and I brought it home. Did I drink it with my lunch? No! I used it to clean my bathroom sinks!
Soda has a good amount of Phosphoric Acid in it and although not such a high pH, it's good enough to clean the germs! All you need to do is to block the drain, pour some Soda, add some water and wait for a couple of minutes or longer depending how dirty your sink is. Then let the liquid drain and scrub with a brush. It will be good as new. The only problem is the smell! I don't know what the hell these companies add to their drink. You can tolerate that or use an air freshener after clean up.
(Photo: The Coke bottle, the brush and my sink. ready to go!)