crontab for super cache?

I was wondering if someone knew of a way to crontab or automate the “delete cache” button in the super cache wordpress interface. Reason being, if I don’t go back in there and press it manually about once a week, the number of cached pages dwindles steadily until I go in and find that about 8 pages are cached (out of 500), and server load is high.

If I could crontab this button (delete cache) to run every day I’m sure the cache would stay in place … any ideas for going about this?

PS — not sure how this ended up in “Installation,” I’ll move it if I can find a way to do it …