Go to your local Ace Hardware store or similar and get a 0.250" brass rod. Will cost you maybe $8. Carefully insert it into the barrel. Mark it where it touches the muzzle. Then wrap that spot with one wrap of electrical tape.
Reseat the brass rod. Tap with plastic mallet or similar hard enough to dislodge the case.
Do not use a cleaning rod. It will simply bend.
Here's hoping you were interested in removing the stuck case. And not something else.