Of course you can, but should you? I believe mixing metallics is possible, but it can be difficult. To me it's like trying to match reds, typically impossible. Well near impossible without a plan.
The plan is to purchase a few multi-metal accessories. Grab a yellow and white gold ring or bracelet, pewter and antique bronze necklace or earrings, or copper and anything, then keep mixing. I love copper colored jewelry, done correctly.
I have a fun multi-metal necklace. It's antique bronze and pewter. I pair it with pewter earrings and antique bronze, antique copper, and pewter bangle bracelets. The metal accents on my handbag and shoes are pewter, but the sheen differs. However, it all works, and it works well.
Use the same concept with metallic clothing and accessories. There's a gunmetal sequined top I was obsessed with for weeks. When I noticed the last one in my size, I purchased it to just to figure it out later. I had it about a year before I felt I owned the right accessories for it. But, then I hated my choices. I was drowning in sterling silver with onyx accents. It was disgustingly matchy matchy! I tried too hard. My successful pairing included multi-metal chain necklaces, oxidized sterling silver and onyx cocktail ring, and black and white gemstone bracelets with sterling silver, pewter, and copper bangles. Sounds like a lot, but with black trousers, a dark wash denim jacket, and black wedges it was glamorous!
You can also get metallic creative with other pieces, hardware on your accessories, or another metallic clothing item. Thinking about it now, that top would be beautiful with a metallic jacket. It's gunmetal with shiny gunmetal sequins, but it's lacking some flare that would be complimented with other metallic clothing pieces.
The moral is that mixing metals is easily done when there's a cohesive approach. It's the same rules for all style, but without cohesion there's chaos!