My one addition to this excellent comment is that the rinse water often  
becomes a hazardous substance that should not be flushed down the toilet because  
it can have harmful effects down the pipes. A private conservation firm which  
cleaned a number of brass and bronze artifacts for the U.S. Navy for the Fort 
 Guijarros Museum Foundation had to contract with a hazardous waste disposal  
company to meet EPA disposal standards. Just keep in mind that the by 
products  of cleaning can become another consideration.
 
Ron May
Legacy 106, Inc.
 
 
In a message dated 4/13/2008 11:24:45 A.M. Pacific Daylight Time,  
[log in to unmask] writes:

While  many of the postings mentioned using weak acids to clean the buttons 
none of  them referred to the need for rinsing afterwards.  I would like to  
underscore the critical need for rinsing after using any acid.  If you  don't 
the acid is likely to remain on the surface and can be activated by  moisture in 
the environment causing long term instability and even eradicating  the 
inscriptions for which you were searching.  I would recommend rinsing  for one hour 
in deionized or distilled water.  If you cannot run the  water gently over 
the piece, make sure to change it several times during the  course of the hour.

Typically we avoid chemically cleaning copper  alloys.  Chemical cleaning is 
hard to control.  It can remove  important information such as textiles 
fragments, stitching fragment, metallic  washes, organic coatings and enamels that 
could be present on some  buttons.  Additionally, it can affect elemental 
analysis by  preferentially removing some components of an alloy.  My 
recommendation  is that before you chemically clean any copper you examine it under a  
microscope with both raking light and overhead light.  Often inscriptions  can be 
read in this manner or some judicious and gentle mechanical cleaning  can be 
used to remove large areas of concretion.

Emily  Williams
Conservator of Archaeological Materials
The Colonial  Williamsburg Foundation
Department of Conservation--BHW
P.O.Box  1776
Williamsburg, VA 23187-1776
Tel: 757-220-7079
Fax:  757-565-8752





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