They've been known to both wash the salt off french fries and dip chicken nuggets in sauce packs.

Anyone who's ever argued that you shouldn't feed crows because it interferes with nature hasn't figured out that crows already adopted to urban human-inhabited environments, and feeding them quality food (cat kibble is cheap and works) is very much a net positive. If you see crows with white feathers, that's malnutrition, and you should give them something good to eat.