I found and inexpensive method for cleaning the vent in my inline breech plug.

It's simple as flossing. Oral-B Super Floss, Dental Floss (Info Link Below)
Oral-B Super Floss

You get 50 of these flossers for around 3 bucks at most drug stores or WalMart. This is enough for years of cleaning.

They are Pre-Cut Strands designed for braces, bridges. They have a stiffened-end dental floss threader, spongy floss and regular floss.

Add your favorite cleaner, push the stiffen end through the vent, pull it back and forth a couple of times.

Much better and cheaper than the pipe cleaners, and you can use them on your teeth as well.