Brass

Samantha de van Geer <sam.vandegeer [at] oxfordshire__gov__uk>
writes

>I am wondering if anyone can advise me on the more appropriate
>conservation materials for cleaning Social History post-18th century
>brass.  We have prelim, brasso, biox, Solvol Autosol and Rubin Brite
>in our conservation cupboards.  I know that Prelim is safe to use
>but is not effective on very badly tarnished and corroded surfaces.
>Can anyone advice me whether any of the other materials we have are
>appropriate and whether there is anything which we should be using
>that I have not listed. I would also like to know if there are any
>up to date articles out there on this matter.

To the best of my knowledge, Brasso contains ammonia or a close
relative of ammonia. Stressed brass exposed to ammonia can crack (it
is called Stress Corrosion Cracking). Please check the current MSDS
sheet or your equivalent for chemical composition. As it is
difficult to determine if there is any significant stress in the
brass objects that you are "cleaning or polishing", it is best to
err on the safe side and avoid any use of Brasso on Historic
Objects.

Jim Moss
Horological Conservator
Professional Associate, AIC Retired
USA


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                  Conservation DistList Instance 22:48
                Distributed: Thursday, February 26, 2009
                       Message Id: cdl-22-48-004
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