We have a brass ornate round salvage piece.  It is vintage, unsure of the exact date or use of this piece.  It could have been salvage from a lamp?  It measures about 1 7/8" across the center x about 3/16" in D.  The center hollow measures about 3/8" across the opening.  It has tarnish and staining on it - I did not attempt to clean it other than with a damp rag.