This was originally sent just to the originator, but thought I 'd share it
with the list. 

With my '82 stock vanagon, the middle carpet comes out if you take up the
aluminum threshold anchor strip by the sliding door.  You can then put it on a
concrete driveway and hose it off and, scurb with a mild detergent if
necessary.  The carpet in the front driver and passenger foot wells can be
throughly rinsed with a garden hose if you do one side at a time, limit the
water to the carpet areas and park the van on a slope so that the water is
encouraged to drain out the open door.  I have done this on both sides at one
time or another.  On the driver side because of spilled brake fluid and on the
passenger side because of a spilled soda on the carpet.  After you are
finished with the hose, you can lift up the carpet enough to remove the hard
foam pad between the carpet and the steel floorboards (at least on a diesel
van) and use an old towel to dry the excess moisture on in that area and to
dry off the foam pad before putting it back.  If you use your hand to squegee
the excess water out of the carpet, it dries pretty quickly if you have good
ventilation (leave the doors open)

Harvey