I've done it! I've created an air freshener that runs on residual milk from my daughter's sippy cup. I dropped her off yesterday and took her sippy cup to work with the unused milk. I figure milk's mostly water, so I used it to "water" my drooping pothos. I guess it took about 24 hours to cycle through the root system. My office now smells like sour milk. I don't want to toss the pothos but I don't know how much is left in the root system. The plant looks fine, it just smells absolutely awful.
Stinky, yet fascinating.