I've got the same problem with my various tubes. I have a set of three aquarium lift tube brushes for cleaning spigots & such. They clean the part of the tube they can actually reach real well. But I need a longer one. They have bendable,long handled lift tub brushes for cleaning keg lines. hold on,I got a place to look. **The keg lift tube brushes are 34" long,but the brush is only 1/4" diameter. Most of the tubing we use for autosiphons,racking,& bottling wands is 3/8". Gotta keep looking.
Everything works if ya let it-Roady(meatloaf)