On Tue, 08 Dec 2015 20:09:11 -0500, wrote:

Stuff a pipe cleaner into the tube. I works a bit longer.

longer than totally clearing the tube??? I don't think so. And the
pipe cleaner can bet "glued in" by the foam too. When I rinse with
acetone and blow the tube out, it's pretty much as clean as new.

Pick your poison. Can't speak for everybody. YMMV