Put ketchup and sprinkle salt on them. Let set 10 minutes then rub good.
Bar Keepers friend works on copper pots. Also, I found this article that might help: https://www.worldcoppersmith.com/clean-copper-pans/
There are copper cleaners available at the store.
I use Comet cleanser on mine
Here's a tutorial on how to restore your copper pots: https://rainonatinroof.com/how-to-clean-copper/