Re: Stuck Ball Bearing
Take the cap off and try to get it out. If it's really stuck in there use a long and thin piece of metal and poke it out from the inside. After that give the ball bearing and the purge port a good washing and then use olive oil to help prevent this in the future.
If you really want to fix this problem you can replace the ball bearing all together with an airsoft BB that is far less likely to get stuck.