What is the origin of the idiom ' pop your clogs?

To 'pop' - slang for taking something to a pawnbrokers. Clogs were used (umongst others) by poor millworkers in the North of England in the 19th/early 20th century. 'Popping your clogs' indicates the wearer was no longer in need of them, so is taken as being dead/dying (normally assumes natural death). Pawning something as important as your footwear would be the last thing you would do...