Nice, but not a significant path of infection. If every surface was covered in copper, that might help, but most transmission seems to be by droplets or even exhaled air. Cholera usually comes from contaminated drinking water, so just maybe those coppersmiths had water vessels made from copper! That could sterilize the water if it sits in the vessels for long enough. Maybe they even had cisterns made out of copper! You can do the same water trick with silver.

Interesting development: Some news of chloroquine and even quinine letting zinc into cells. (Without such help, zinc does not get in.) So you need both zinc ions outside the cell and one of these zinc-helpers present. Zinc inside the cell interferes with virus RNA replication. I assume it would not be 100% effective, or it would have been discovered a long time ago. Still, it might give your immune system time to mount an antibody response. News flash: They are using this in China.

Fierce Pharma

Chloroquine is an old, dirt cheap prescription drug for malaria. There is some talk about azithromycin killing Covid-19 as well. If this works, it could mean we never reach the point that we run out of ventilators.