When visiting Smailholm tower in the borders of Scotland, I found a display of artefacts dug up around the tower, and something else, a common error that is repeated many times in many places:
I have been unable to find any evidence for this practise, nor has anyone in places I hang out online ever put any forwards. A quick reality check argues against it in the first place, due to the difficulty you would have in getting into and using a garderobe if it was full of clothing, and the factthat medieval people didn’t like the smell of garderobes any more than we do, and so having clothes which smelt of it would be unlikely to appeal. It seems to be another zombie myth, like the one about knights in armour being unable to stand up or get onto their horse by themselves, or that spices were used by medieval cooks to hide the taste of the rotting meat, or that swords were incredibly heavy.
The reality is that they hung clothes up to air and packed them away in chests, often with herbs of various kinds to try and drive away moths and make their clothes smell nice.
A black letter work by Laurens Andrewe, quoted in page 10 of the introduction to the English translation of Le Menagier de Paris by Eileen Power (2006 Boydell reprint) states:
The mothe bredethe amonge clothes tyll that they have bytenit a sonder and yt is a maniable work, and yet it hydeth him in ye clothe that it can scantly be sene and it bredethe gladly in clothes that have ben in an evyll ayre, or in a rayn or myst, and so layde up without hanging in the sonne or oether swetre ayre after … The erbes that be bitter and well smellinge is good to be layde amonger such clothes, as the bay leavis, cypres wode.
Which accords with best practise treatment of my woollen re-enactment clothes- dry them out, air them in the sun, and then pack them away in a box or chest of drawers or suchlike.
Moreover, if the smell of urine and excrement was supposed to keep them away, why is such a practise not mentioned in Le Menagier de Paris, nknown in English as “The Goodman of Paris”, the late 14th century guide to looking after a household written by a rich paris merchant for his young wife? On the topic of moths it simply says:
Concerning which know you and tell you your women, that in order to preserve your fur coverlets and yours stuffs, it is meet often to air them, in order to prevent the damage which moths may do unto them; and because such vermin gather when the cold weather of autumn and winter groweth milder and be born in the summer, at such time it behoves you to set out furs and stuffs in the sun in fair and dry weather
I think we are entirely justified in viewing it as a horrible old myth. Maybe it arose from garbled accounts of the use of urine to bleach linen. Maybe it was a genuine countryside practise in some parts of Europe that nobody else did, but has been stupidly generalised to all countries in the medieval period. Either way it is a pernicious myth which should be destroyed.