How to remove old modules from Jenkins?

[Dan Halperin <dh...@google.com.INVALID>]

See, for example:
https://builds.apache.org/job/beam_PreCommit_MavenVerify/2530/ The list of
modules is mostly grey (didn't run).

Some of these are modules that once existed, but have since been refactored
away. Others were introduced in a pull request but were never actually
committed. (e.g., the nicely typo'ed Apache Beam :: SDKs :: Java ::
Microbenchamkrs)

Google tells me I should be able to "Delete all disabled modules" (
https://issues.jenkins-ci.org/browse/JENKINS-4561), but I can't find that
command. I *can* do things like configure PostCommits, etc.

Am I missing something obvious?

Thanks,
Dan