One of Manzoni's friends, Agostino Bonalumi, claimed that the tins are full not of faeces but plaster. The cans are steel, and thus cannot be x-rayed or scanned to determine the contents, and opening a can would cause it to lose its value; thus, the true contents of Artist's Shit are unknown.
The can's contents were difficult to identify on sight, being variously described as "paper wrapping with unidentified contents", "an unidentifiable wrapped object" and "a can within a can". Bazile did not attempt to extract or open the inner object.