E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Gone to my uncles. Uncles is a pun on the Latin word uncus, a hook. Pawnbrokers employed a hook to lift articles pawned before spouts were adopted. Gone to the uncus is exactly tantamount to the more modern phrase Up the spout. The pronoun was inserted to carry out the pun. In French, Cest chez ma tante. At the pawnbrokers.