One handy item to have if you're going to use a vacuum machine to clean
your tracker bar is a thing known as a "tit cup".  It is a milking
machine insert.  When slipped over the end of a crevice tool on the
vacuum machine it allows you to really get a good seal on the tracker
bar.

The "tit cup" being flexible is useful for a number of other
applications where you might need a rapid movement of air in a small
space.  For many years I've also used one for cleaning out old
equipment that had dust or dirt in it, also for cleaning electronic
gear.  One can often be obtained for the asking at a farm equipment
place or from your local dairy farmer.

They do sometimes become unsuitable for their intended purpose but that
does not affect them, as far as our use is concerned, as long as you
don't try to blow milk through them.

Hal Davis