Such crosses were worn by the choir members (and still are) over their cassocks & surplices. We are, of course, quite taken by ours as they are vintage.
This style of cross would be excellent for assemblage jewelry as the surface on either side is absolutely flat - so that you can add your embellishments easily with adhesive or solder. Or, you might choose to change the ribbon that holds them and add a chain or leather thong for a different look.
We have not cleaned them in any fashion - that's up to you, should you choose to do so! Many of them are patinaed and look even better (we think) than they might have as new.
The cross measures 2-1/4 inches tall by not quite 1-1/4 inch from side to side. Each cross arrives with a black braided cord or ribbon.
One side is completely plain and on the other side at the top is a small makers mark with the letters S and F with an arrow through both.