You can clean an antique copper faucet. However, you may not want to. If you clean the piece it could lose its patina which takes away from its value. If you do clean it, use soap and water and be gentle.
Antique faucet parts can be purchased online and at local antique stores. Online, antique faucet parts can be purchased at Vintage Tub, eBay, and Plumbing Direct.
A copper kitchen faucet offers more fresh water compared to the stainless steel faucet. The copper kitchen faucet also has more powerful water energy and valves.
There is a product called CLR which is available in grocery stores which removes lime deposits.
The molds are worth more than the value of the copper (provided they are indeed antique) so don't scrap them.
Vinegar.
Antique copper trays can be hand-hammered and coated in various materials such as silver or gold. They can be circular, square or rectangular and may have handles.
Copper.
Take this to a reputable antique dealer
You can purchase antique copper on any online marketing like ebay or amazon. Great places and low prices overall. They can be in mint condition or kinda used.
One can clean a brushed nickel bathroom faucet by using gentle soap with soft cloth to scrub the surface. One can mix vinegar with water to gentle scrub without scratching the surface of the faucet.
You did not state what the sculpture was made from. This would determine how you clean it.
Unscrew the aerator and clean it and reinstall it