How can I remove several coats of paint from my copper gutters to restore them like new. They are still on the house and I would like to not have to remove them to do this
home centers or hardware stores sell a paper scoring tool that you should use to perforate paint and paper. It makes several small holes. Then you can put wallpaper remover on. You can buy it in a spray bottle. Where gloves spray and wait for 15 minutes or so. Its not easy, but works. Just keep soaking it. You might have some wall repair to do (texturing or light patching for smooth walls)
"like new" not possible. Removing the paint, possible, but probably not practical.
Heat would work, like a torch, as long as you don't unsolder the joints or set the cornice alight!
Chemical strippers would affect all other painted surfaces, cars, pets, beneath.
Abrasives to be avoided on the copper, because you don't want to thin the metal, even a tiny bit.
There is only one safe reasonable way to strip the gutters and you will probable save time in the long run. Remove the gutters and take them into a commercial chemical stripper place where they will dunk them in a bath of chemical stripper and wash it clean. It would be extremely labor intensive for you to remove the paint while the gutters are still hanging and potentially dangerous depending on how high they are.