Well, I find myself stuck, much like the bolt ona cast iron drain pipe I need to snake out. Can't seem to make it budge, am running out of ideas. Maybe I should replace the cast iron pipe (running from a laundry tub), might be easier to do that! Wish I could just plunge the clog, which is probably years of lint from the previous owners. Any ideas, anyone?
You're trying to remove a cleanout cap, right? What are you using to remove it? If it has been there for a long time undisturbed, it could take quite a bit of leverage to get it loose.
Laundry clogs can be a challenge because the lint forms a paste that's the consistency of mashed potatoes. You can run a snake right through it and not do any good at all in a lot of cases. I've had mine professionally cleaned and have had excellent luck maintaining it with enzyme drain cleaners.
You can replace the cast with PVC. It isn't terribly difficult, but you'll need a special tool (rental) to snap the cast iron off. Transitions to PVC can usually be made with Fernco bushings. If you want to post pictures of what you're dealing with, we can walk you through it.
When trying to release anything threaded try this. Don't just try to turn it counter clockwise. Try turning it back and forth for a while. If it starts to come loose just keep going back and forth. This works much better than just trying to bully it out in the counterclockwise direction. Heat also helps a little. Buy a cheap heat gun. They're just a blowdryer on steroids. They will put out alot of heat without damaging the work. You can also drill out the center of the plug. This will help release the pressure on the threads.