When you are working with vintage finds you want your new pieces that you mix in to blend. I like to add a darkend sparkle chain to my fringe. Many chains are made in raw brass as are many other findings and can easily be darkened to blend.
Just place in an airtight container with a smaller container of household ammonia...yes it looks like urine here and also smells like a litter box! speaking of litter boxes...you can actually put your pieces in one, but that would require digging them out...
Leave in the container for several hours with the lid on tight and viola! you have beautiful dark peices. The crystals in this chain are unaffected by the ammonia, just the brass of the chain.