Get a pair of "odor eaters" shoe liners. The back of those things is really grippy. Wrap the grippy side around the thing and loosen it up.
It always feels like it's gonna break when you do it bare handed. I've used the shoe liners to unscrew plastic
tank sections that I was sure were going to shatter when I was trying to loosen them bare handed. Thing is, you've got to get it loosened. If it's gonna break, it's gonna break no matter what. What else can you do?
*Edit...those pad things for unscrewing jar lids also work, and so do mouse pads with "rubberized" (or whatever it is) backings.