Welcome, Beena. Two thoughts: 1) Find some pre-1982 Lincoln cents and try cleaning them with the aforementioned method or any other method you might come across. If the pink-ish hue imparted to the copper doesn't bother you, then it's all good. After all, we're talking art/fashion here, not numismatics. A color isn't "wrong" if it's a color that pleases you with respect to the intended purpose. 2) If you do #1, be aware that the coins will begin the toning process all over again. If you don't want that to happen, consider applying a lacquer finish to stabilize the color. The lacquer will also give it a more polished/finished look.
Thanks! I plan on making a translucent colored polymer clay bezel and then sealing the entire piece with a self-doming jewelry grade resin. Another thought-because I have the waxy luster pigments, I can always gently tint it if it turns too pink. My main concern was chemically eating the details off of the piece. If 1860s copper is sturdy enough for vinegar/salt, I'll be in good shape
Copper just isn't going to look how you want it to look when polished. If you're really that concerned about having something shiny, then you should go with silver.
I hear ya'...unfortunately, there was nothing silver from Italy that was cufflink-sized from 1861. I even tried 1874 because that's when the Verdi Requiem was finished, but no luck.
The 1861 50 Centesimi is basically the same size, and it's 0.900 fine silver. There are several other similarly sized silver options as well if you want to go with 1861 Papal States, Sardinia, or United Provinces of Central Italy.
I took a look on Ebay and was only able to find one...and it was damaged...plus a bit too expensive for me. But I will keep looking. Thanks for the heads up! Can't believe I missed this one.
Go to a local coin shop and look in their sale/ junk bin. You won't leave without getting something. You won't be disappointed.