Means completely, utterly dry, with zero moisture left. You can use it for washing, weather, your throat after a night out, or a fridge that’s been rinsed clean by greedy housemates. It’s a proper everyday phrase, not fancy, just dramatic enough to make the point that there’s absolutely nothing left.
"You got any milk for a brew? Nah mate, carton’s bone dry, someone’s rinsed it. Same with the biscuit tin, looks like a herd of toddlers hit it at 3am."