Since Ward has figured out that things exist and some of those things hold liquid that can be sipped, no vessel is safe. Waste baskets, measuring cups, an empty can of black beans pulled from the trash can. And he doesn't seem to care if there is actual liquid in these things...he acts exactly the same after tippin back an empty Triscuit box as he does when drinking his milk (he smacks his lips and lets out a big satisfied sigh like he's in a Coke commercial).
Okay, this is an actual cup. But it's just full of Cheetoh's.