How to remove, clean, and replace car battery terminals?

Yes… and the shop can let the Op watch. That’s how I learned, half a century ago.

I don’t know of any shop that will let you watch anymore, liability insurance usually doesn’t allow customers in the shop.

Yes, I hadn’t thought of that… for the dealer. The parts house had no indoors, and the tire shop works under an awning for batteries. They were always willing to explain what they were doing to my son and wife.