Sealing Copper Jewelry with Spray

After having read online about spray sealing metal jewelry to protect it I grabbed some Aleene's Spray Acrylic Sealer Matte Finish at Michaels.  That was the only thing I saw at the store that mentioned sealing metal.  I had hoped to get a finish that would be quick to apply and long lasting.  I tried it out on my copper leaf brooches and pumpkin pins with a heat patina.  The matte finish looked nice but the sealer scratched off too easily to use for my jewelry.  You can see the mark my fingernail left on my pumpkin brooch when I scratched it over the surface.  I could even peel the dried coating off in one piece.  The sealer deficiently didn't work for the application I bought it for.  I'm sure it would have more staying power on a rough metal surface or a piece that didn't get as much handling as jewelry.  For now I'll go back to sealing my pieces with paste wax.  Feel free to leave comments on your experiences with sealing copper or other metal jewelry.