JIRA Automation: Clear field upon transitioning issue?

[csu]

I'm using the JIRA Automation plugin to transition issues from one status to another in a workflow. It offers the ability to set field values, but is there any way to clear a field?

I've tried to achieve the same result by adding a post-function to the transition, but the function doesn't seem to be triggered when the issue is transitioned by the automation plugin (maybe because I didn't specify a specific transition between the two statuses, but rather added the post-function to the all -> new status transition?).

[csu]

Update: the post-function wasn't working because I never published the workflow draft and every time I went back to "confirm" that the post-function was set, I clicked "edit" instead of "view" and opened the same draft.