Ye gods, thought Moist, back in the here-and-now, no wonder Groat sucked cough sweets all the time, the dust in this place could choke you!

He rummaged in his pocket and pulled out the diamond-shaped cough lozenge the old man had given him. It looked harmless enough.

One minute later, after Mr Pump had lurched into the room and slapped him heavily on the back, the steaming lozenge was stuck to the wall on the far side of the room where, by morning, it had dissolved quite a lot of the plaster.

— Going Postal by Terry Pratchett, Terry Pratchett (Page 66)