Use copper ingots to craft tools and armor.
Copper Tools
Copper tools are faster than iron, but lose durability quickly.
The tool will oxidize as it's used. As the oxidization builds up, it will get slower but more durable.
Unoxidized tools lose 4 durability each time they're used. A fully oxidized tool loses only 1 durability.
Oxidization Poison
Oxidized tools have a small chance of poisoning any mob they hit.
Scraping
Right-click on a grindstone to scrape oxidization off of a tool and repair it.
This will also erode some of the tool's max durability, making it weaker over time.
Or repair with an axe in an anvil.
Copper Armor
Copper armor will oxidize as it takes damage.
When hit by an axe, there is a chance the armor will be repaired.
