How to clean copper

So, how do I care for my copper collection?
I love the warm patina of antique copper but occasionally, it needs a good shining to remove tarnish. Restoring the luster of old copper doesn't need to be a daunting task.
My cleaning go-to for my copper collection is ketchup. If you are like me, the less chemicals in my house, the better. It can take multiple applications for some antiques, as you may have years of build-up sitting on top of the tarnish, but it does work fairly well.
If you can't get everything off, then try a chemical agent but for many tarnishes on copper, this can be the easiest and safest route for this problem.
You will need:
paper towels or clean kitchen towels
plastic brush or plastic sponge
ketchup
​kitchen gloves (optional)

Wash your copper in hot, soapy water and give it a gentle scrubbing with a plastic brush or plastic scrub pad (Do NOT use metal brushes or metal sponges as it will leave fine scratches on your copper). Dry thoroughly. Washing your item first will help remove  the surface grime or at least soften it for the ketchup to be able to work on the tarnish. Next, lay down paper towels or a kitchen towel to protect your working surface. Pour just enough of the ketchup on it that it has a moderately thin coat all over it and smear it in all of the crevices of the copper item. If you still have discolored areas, apply again and let sit for 10-20 minutes and rinse again. Keep repeating the steps until it is to the desired patina. Lastly, wash your piece with hot, soapy water, making sure to remove all ketchup from the creases and rims; then rinse well and dry.
It is an easy way to clean and bring that luster back to your copper without using harsh chemicals. Give it a try! - Katie, Katie And Company®

The #1 photo shows a 6" vintage pan that has not been cleaned yet. The #3 photo is a teaspoon of ketchup that I added to show you what it did after sitting for 10 minutes. The #4 photo is the pan after it was moderately coated with ketchup and let sit for 10 minutes.