Removing brass polish residue

I am a conservation intern trying to determine the most effective
way to safely remove polish residue from a large collection of
historic brass objects.  Many of these objects are incised or
pierced with residue in the interstices.  What literature exists
describes basic mechanical cleaning with a bamboo pick as the
preferred method; however, due to the quantity and type of objects
in need of care, we are looking for something more efficient and
effective, even if only to loosen the deposits enough to speed up
the mechanical cleaning. Most of what we have found written on
copper alloys addresses active corrosion on archeological objects,
so it isn't of much use to us.

We have tried several treatments with varying degrees of success
including steam cleaning, soaking in EDTA with a pH of 8.5, warm
water, warm water with a surfactant, brushing with a toothbrush, and
a sonic bath with both tepid and warm water.  Does anyone have any
further suggestions?


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                  Conservation DistList Instance 25:39
                 Distributed: Friday, February 24, 2012
                       Message Id: cdl-25-39-022
                                  ***