Cannot remove keg pressure relief

[BeerFather Brewing]

So I bought a bunch of used 5g kegs off Craig's List. Hell of a deal, actually. They needed a little love, but nothing major.

I did run in to one issue: the plastic portion of the pressure relief on one of the lids is partially broken making it difficult to remove/replace. Any ideas on how to remove it/unscrew it? I am mildly perplexed but figure this is likely not a new issue for the community.

 

[LandoLincoln]

It looks like the plastic top busted off. That's how you'd unscrew it. Now you're going to have to use some brute force to get that thing out. I'd use a scratch awl and pound it into the plastic and then try to rotate the plastic counter-clockwise.

This is what they look like with the plastic top intact.