Coke Can Clean Your Toilet in a Pinch
from Lifehacker by Gina Trapani
When your toilet’s got rings and lime scale stains and you’ve got no cleaning gear on hand, grab a can of Coke out of the fridge.
According to wikiHow, you can pour Coke into a dirty toilet and the carbonic, citric, and phosphoric acids in it will break down stains, especially if you can leave it overnight to do the work. (Soda water will work too, without all the sugary residue.) Be warned though: this technique won’t save you from the dreaded brushing of the bowl itself.