One of my all-time favorite drawing tools is the Pentel Pocket Brush pen, a cartridge brush pen ("fudepen") with a bristled tip instead of the more common flexible nylon tip.
Unfortunately, I went through a rather lengthy spell where I wasn't drawing, without also realizing the cartridge on my pen had run out. When I picked it back up recently, even with a new cartridge and allowing the pen to sit tip-down overnight, I wasn't able to get a good ink flow through the pen, only jagged, pale lines. This leads me to believe that, due to the empty cartridge, the ink in the feed had started to dry up and has clogged the pen.
Because the ink is both water- and Copic-proof, soaking in either plain water or alcohol is unlikely to loosen the ink from the feed and allow it to flow through again. Because of the name of the pen being composed entirely of extremely generic words, it's also tough to find much information on whether anyone's had success reviving a dried Pocket Brush. So far, I've found no evidence anyone's tried to do so, much less what procedure one might use to attempt to revive the pen.
What might one do to restore the ink flow to a partially or fully clogged bristled brush pen, if anything?
(Note that I have already replaced the pen with a new one, so anything that I'm able to test can be tested on it without risk of ruining my only pen; it's already ruined, so I may as well donate its body to science!)