Everyone who has shot a Glock has experienced it: You’re shooting a string of fire, the slide locks open and you go to perform an emergency reload only to find the magazine stuck in place—it can be quite frustrating. How can you fix it? Clean your gun differently.
Many Glock magazines stick due to solvent or lubricant in the magazine well. To avoid this, clean the polymer frame with a baby bottle brush, dry scrubbing the dirt and debris out. These brushes have a wide but soft bristle that is designed to work well on plastic. You will see the crud come out quickly and easily compared to trying to get a cleaning patch into the nooks and crannies.
Once the frame is clean, apply a coat of car wax to both the inside of the magazine well and the exterior of the polymer magazine body. Just like on the body of your car, the wax will dry and become pasty. When it does, take a clean rag and buff both the magazine well and the magazine body. Make sure you get all of the dried wax away from the inside of the magazine release button. Your magazines should now jettison cleanly away on a reload.