For about a year now i have been installing the Dirt Collector to the AB Valve. The Dirt Collector is included in the Tichy "AB" Brake Set and on the Styrene Sprue of the discontinued Grandt Line/Detail Associates sets. IT is in some Westerfield kits like the ATSF Bx-11/-12/-13 series of kits.
Today as I was working on my CB&Q XM-17/-18 kit I started to wonder what to do as there was no Dirt Collector in the kits resin AB brake parts I was assembling. I could use a rob a Tichy set or a GL/DA set but I would still be short when I used one of those sets. Hmm. Wait a minute, there are Dirt Collectors on the rear end of the Tichy KC brake cylinder and I have several of those sitting around so i took a closer look. If I clipped it off just so, it would leave a piec long enough to fit into a hole drilled into the resin AB valve I was using. It I trimmed the other end just so, it would be wide enough to drill a #79 hole. The photos show the result.
Now I also have a backup if I drop one of the Tichy or GL/DA parts.