A Scotsman Loses His Jacket

A Scotsman is working at a sewerage. It's a warm day, so he takes off his jacket and drapes it over a handrail where it slips off into a vast tank of poo. He's just about to dive in when his mate shouts

"It's nae guid tae do that, the jacket's ruined!"

He replies "Aye, ah ken, but ma sandwiches are in the pocket."