/var/folders taking up a huge amount of disk space

[ryandesign (Ryan Carsten Schmidt)]

On the 10.9 buildbot worker, /var/folders is taking up a huge amount of disk space (17GB out of a 90GB disk). We run out of disk space, causing builds to fail. I don't know how to return it to a reasonable size. I did not check the other workers but they could be affected too.

Much of the space—about 535MB per user, times 28 user accounts created by various ports, about 14GB total—is consumed by the com.apple.IconServices cache directories.