Manifold pipes - getting the plastic bits out...

I've recently upgraded my MLT to a 70 qt Coleman picnic cooler w/ manifold. Manifold is made from 1/2" cpvc. Was less than $15 for all of the parts and fits perfectly. The middle arm connects to the bulkhead fitting with a 1/2 Cu coupling. Here's the manifold:



Slits were cut with a Rockwell Sonicrafter about every 3/16" to 1/4". Dull as dishwater but not at all difficult. The problem I ran into, however, are small plastic slivers that are hanging on to the inside of the custs. I wrapped some sandpaper around a 3/8" dowel and than helped a little, but quite a bit of crud remains:



Any thoughts on how I might resolve this problem?

When I first made mine, I had the same problem. What I ended up doing (and there's probably a much easier way to do it) was taking a long pipe cleaner brush similar to this...



... and used it to clean out as much as I could. After that, I took a razor knife and cleaned out each cut that still had loose plastic hanging. I then cleaned it out with the brush again to clear out all the stuff that I cut free.

It was time consuming but it turned out well.

I did the same as jamboparty. I made the brush longer buy cutting the loop off the end and then sticking it into an old golf club shaft I had laying around.

I used a set of modeling files and a large round file just smaller than the id of the pipe. Worked really well.