Ever wished you could take a shower with pigeon poop? Artist Tuur van Balen proposes changing pigeons from flying rats to cleaning agents. A speculative, specially engineered bacteria, as harmless to pigeons as Lactobacillus is to humans, could potentially change pigeon excrement into biological soap. For Pigeon D'Or, van Balen built a coop that clips to a window, which would allow future apartment dwellers to harvest their very own fresh, pigeon-made soap. Another version of the perch extends over a car's windshield, inviting the birds to come and rain detergent on glass in need of cleaning. Van Balen's "bespoke urban disinfection" won him an 2011 Ars Electronica Award of Distinction. Tuur van Balen will be presenting at the Next Nature Power Show on November 5th. Though he won't be bringing along any sudsy pigeons, he will be teaching the audience how to make their own anti-depressant yogurt.