It was drained so some kind of even more loathsome ichor* can fill it.

*In pathology, an ichor is an acrid, thin, and often foul-smelling watery or blood-tinged discharge that drains from an infected ulcer, sore, or wound. While its mythological meaning implies divine essence, the medical term derives from older ancient medical observations and is associated with inflammation and putrefaction. (Pulled from Google)