We have used a shop-vac often at Jamestown with great results for cleaning
brick rubble. The best use in my experience is for cleaning off The
previously troweled baked out subsoil and tops of subtle features. We use it
more as a cleaning tool rather than an excavating tool to reveal the edges
of more ephemeral post holes/molds etc. Of course we live in a world of
running water and electical outlets!
        We have also recently been playing around with an inexpensive laser level.
These things are fantastic. We are currently excavating on an area with a
20%+ slope so the string/line level set up has been less than satisfactory.
These levels cost about 30 bucks and can be set up at the top of a section
and used in lieu of a string.
                                                                                                        Eric Deetz
                                                                                                        APVA
                                                                                                        Jamestown Rediscovery