Vintage handmade item with original patina intact.  You can clean it yourself or keep it as is.  The product has a hallmark of silver and the letters BAS (presumably the signature of the master).  Please keep in mind that the color of the product in the photo depends on your monitor or phone.

This would have been worn on a vest/jacket or hat.

Stamped "835" for a common European silver standard of 83.5%.