If you have been roaming around the island for some time, you will most likely have stumbled across chests in Palworld, and some of these are locked.
This requires that you get your hands on a Copper Key, which is used to unlock them to get whatever loot is locked away inside.
Copper Keys are consumables that are obtained differently as these cannot be crafted and are instead loot that you pick up.
How To Get Copper Keys?
Copper Keys can be obtained when events occur, which are mostly when your base is attacked by enemies that are human or Pals.
There is only a chance that a Copper Key will drop from these enemies but you should be able to get a few now and then as these raid events happen from time to time.
There is a chance that you may obtain a Copper Key when you open a gold or purple chest, which spawns in random locations.
Defeating bosses also has a chance for Copper Keys to drop and the same goes with Lucky Pals that rarely spawn.
Copper Key Uses
Copper Keys are used to open locked red chests, which can be found in certain locations as you continue to explore the land.
Each red chest will require a Copper Key for you to unlock it and obtain the loot inside, which can be several different items.
Most of these chests will provide you with rare materials, schematics, ammunition, and more as these are randomized.
Verdict
Copper Keys will eventually come into your hands no matter what you do since enemies will attack your base and you are bound to stumble upon chests now and then.
Boss fights can be a good way to get Copper Keys but these may be a bit difficult for newer players while Lucky Pals are a rare occurrence.
The best thing to do once you have a Copper Key is to keep it safe and take it with you after you locate a red chest or to simply bring it with you at all times to be sure.