Solid Copper Kettle from Denmark Knob Missing — Antique

Exciting for me because my grandparents were from Copenhagen, Denmark. Found this at end of estate sale even in its “green” patina finish. On WorldAntique.org this was listed for over $300. The handle moves from one side to other. I started cleaning the bottom, but haven’t found a signature yet. I don’t want to go too far in case buyer likes this look.