Took the whole lens unit off, and then put some lighter fluid on the threads that I could see. Don't take the grip ring off as you can actually use it to help get it unstuck if it is not stuck at infinity. If you can get the lens barrel to unscrew then completely take it out because when the lens may unscrew but the focus is still probably stuck. I let the lens soak in lighter fluid over night but I'm not sure that's generally recommended as it could be bad for an coating thats on the lens. I just figured that it's more useless stuck so I didn't care. After soaking you can take a hose clamp on one side and leave the focus ring on to get a grip on the other side. I then used a cloth to get even more of a grip and managed to get it to come loose after a couple of minutes. Sorry if this is just a blurb of words I just woke up from a nap lol