Cleaning stone

In Cons DistList 15:23, Robert Lodge writes:

>For cleaning building or sculpture stone when high pressure water
>alone (hot or cold) is not effective, I recommend the JOS system. In
>skilled hands it can even be safely used to remove dirt from painted
>exterior surfaces.  We use the system for cleaning a variety of
>materials.  Its use is growing in the United States.

I would like to second that.  I oversaw the cleaning of the
Massachusetts Historical Society building a few years ago using the
JOS system (when the system was new in the U.S.).  It did a
beautiful job of cleaning a hundred years worth of dirt and stains,
with no damage to the surface of the building material itself.  I
took very basic pressure-at-the-wall readings, and found that the
JOS system was much lower than the pressurized water system (I don't
remember the exact numbers anymore).

Joice Himawan
Director, Dyer Memorial Library
(formerly Conservator, Massachusetts Historical Society)


                                  ***
                  Conservation DistList Instance 15:24
                Distributed: Tuesday, September 18, 2001
                       Message Id: cdl-15-24-002
                                  ***