Is there a way to clear the geometry cache?

I'm working with reasonably large networks - all geometry, no dynamics, and each subnet takes a significant amount of memory when cooked (running to >100GB), which doesn't get released even when re-opening the project in the same session: I have to quit and re-launch Houdini.

Hoping I've simply missed a trick I've not had to look out for before.

Did you try the Cache Manager? Under Windows -> Cache Manager, or Alt+Shift+M.

Yeah, and it clears some, but only a little (a little being e.g ~6.5GB/61.5GB, as illustrated in the attached screenshot), despite the cache readout itself saying otherwise.

So the lion's share is still in some mystery limbo. \bug, do you think?