1 The meat was as tough as old boots.
2 She's almost 90 but she's still as tough as old boots.
3 He's as tough as old boots, but playing with drugs is still a mug's game.
4 She is as tough as old boots.
5 But though Zen looks a wet little wimp he's as tough as old boots.
6 And she has shown already, beneath her frail exterior, Kylie is as tough as old boots.