So the nub of the matter is this: Due to circumstances beyond my control some 'yoghurt' got onto the fabric of a chair that I do not own but am in indefinite possession of (until the time comes when I am asked to return it). The 'yoghurt' was identified to have left some markings on the fabric, even after it had been mopped up and later flushed with clean water. The mark left is such that anyone coming across the chair might well think to themselves, "Hey, that chair looks like someone's spilt some 'yoghurt' on it". And so I ask, is it still within the bounds of possibility that this 'yoghurt' mark may be removed without permanent harm being done to the chair, or has the 'yoghurt' bleached the fabric somewhat irreversibly? Should the answer be irreversibility, what then? Should I look to apply copious amounts of 'yoghurt' to the rest of the chair in pursuit of some uniform bleaching effect?