Brass

Rachel White <rachel.white [at] uts__edu__au> writes

>Michiel Langeveld <info [at] metaalrestaurator__nl> writes
>
>>During washing of brass objects in water, the brass stains from gold
>>to brown. Can anyone advise me on the use of inhibitors or other
>>methods to avoid this staining?
>
>I'm not familiar enough with the chemistry of brass to tell you what
>is going on but I can share a method used in our lab for cleaning
>metal. We often clean stainless steal parts of instruments with
>Wenol paste (rubbed on and off with cotton wool to remove staining).
> ...

While using Wenol Paste on stainless steel may be ok, it is my
understanding that brass should never be cleaned with any agent
containing ammonia.  While Wenol Paste is promoted as a detergent,
the MSDS lists both ammonia and aluminum oxide amongst its
ingredients.  The detergent ingredient appears to be a fatty acid
amide, which may also damage brass.

Linda S. Roundhill
Art and Antiquities Conservation
18121 157th Ave NE
Woodinville, WA 98072
425-481-0720


                                  ***
                  Conservation DistList Instance 18:10
                 Distributed: Thursday, August 5, 2004
                       Message Id: cdl-18-10-004
                                  ***