Also free and collectable are the wet wipes (moist towelettes in American) that come with airline meals.

ECONOMIST: Business travel

The pan-fried duck schnitzel is grease-free perfection, crunchy on the outside and fragrantly moist when the knife meets the cutlet.

NEWYORKER: The Marrow

For example, your doctor may recommend that you suck on a piece of sugar-free candy or chew sugar-free gum to relieve dry mouth, and use eyedrops to keep your eyes moist.

CNN: Overactive bladder