YOU can’t polish a turd, so the saying goes. But you can turn it into homeware, as a new material called merdacotta proves. Made out of clay and cow excrement, merdacotta—literally, “baked shit” in Italian—can be fashioned into tiles, tableware, flowerpots and, fittingly, toilet bowls. An installation of items made out of merdacotta was one of the most memorable offerings at this year’s Salone del Mobile design extravaganza in Milan. Luca Cipelletti, an architect who helped to devise the exhibition, says that “people smile and think it’s funny to talk about caca, but behind it all we are exploring interesting and philosophical ideas about man, art and nature as well as the concept of transformation.” The merdacotta story started when Gianantonio Locatelli, a farmer in northern Italy, realised that his 2,500 prolific pedigree bovines were producing 30,000 litres of milk a day, as well as a staggering 100,000 kilograms of manure. Keen to do something productive with this noxious by-product, he invested in several state of the art digesters that could transform the excrement into fertiliser and methane gas for electricity. The next step was to extract the urea (from which plastic is produced) and dry out the remaining de-methanated concoction and use it as a raw material to make plaster, bricks and other objects.

A later encounter with Mr Cipelletti, as well as conversations with Gaspare Luigi Marcona, an artist and curator, and Massimo Valsecchi, a collector, gave birth to the idea of a Museo della Merda (“The Shit Museum”). It was launched in May 2015 as a series of outdoor and indoor installations, with the latter presented as a cabinet of curiosities in a late medieval castle on the grounds of Mr Locatelli’s farm. The pieces highlight the site’s innovative and sustainable approach to agriculture, as well as faeces’ lesser-known place in history as a construction material for ancient civilisations, or indeed as an essential ingredient in many curative potions.

Photographs and videos reveal the different phases of the merdacotta process. One video shows a Locatelli bovine taking an incredibly lengthy (and noisy) dump; another shows a tractor arduously moving tonnes of crap. The images are unforgettable. Elsewhere, canvases by Italian artist Roberto Coda Zabetta are decorated with a highly textured blend of excrement and pigments. The exhibition ends with a strikingly majestic 200m year-old dung fossil (or coprolite), and an impromptu gift shop selling merdacotta mugs for €10 upstairs.