We've done TONS of work with Kodi on resource guarding since he was a pup, because of his "addiction" to paper. (he doesn't shred, he eats it!) We HAD to be able to get non-food items away from him, to keep him from hurting himself. For a LONG time, we would "trade" for a high value treat. And they had to be BIG treats, because if there was a way that he could snatch the treat AND keep the contraband in his mouth at the same time, he would!
Then, we would set up situations with a high value chew (like a Himalaya Chew) that he didn't want to give up. With these, we'd ask him to give it to us, saying "drop it" and putting our hand under his chin so it would drop into our hand. Then we'd give him something yummy, and hand the chew back.
Now he will hand us "contraband" without a "trade" in sight, even if you can see in his eyes that he REALLY doesn't want to. But he then RUNS to the kitchen to collect his cookie.
It literally took years to get to this point though... he's only been reliably dropping "treasures" within the last year.
When he was a puppy, there were times when we had to pin him down, pry his mouth open and go on a fishing expedition to retrieve really bad things.
Certainly not an"approved training strategy", but sometimes ya gotta do what ya gotta do when they have something dangerous in their mouths.
The first time he HANDED me a kleenex when I asked, I just about fell over! For a LONG time, his default answer to that situation was "swallow fast"!