I’d super glue it to sacrificial stock, then release it with acetone afterward, probably wishing that I had pure nitromethane instead, since I haven’t yet ordered a quart for $60:
I think I’d try it on MDF first so that acetone could soak through from the other side to release it without bending.
Also, because it’s brass, you may have to be careful about which mill you use. Dunno whether you have milled brass and know how “grabby” it is.
Stefan Gotteswinter put up this video a couple months ago that might be worthwhile:
