Rinse them off and clean all the pumpkins strings off off them. When they are wet, sprinkle a heavy load of salt over them.
Place in a single layer on a cookie sheet and bake 350 degrees just until the salt is dry. If you brown the shells, the seed inside will be over done.
We don't suck on the shells, just put them in our mouth to crack them so the amount of salt is right. If your family sucks on the shells, cut back on the amount of salt used. Perhaps just soak in salted water and then drain and bake.
I eat shells and all. I have 2 ways to cook them. First, use about 1 - 2 tbsp veggie oil, toss the pumpkin seeds in the oil lay them out on a cookie sheet and sprinkle with salt. Roast for 20 - 30 min at 350. Stir a few times while roasting. This year I found a recipe where you use butter (2 - 3 tbsp) and toss the pumpkin seeds in melted butter, spread out on cookie sheet, sprinkle with salt and roast at 350 for 20 - 30 min. stirring a few times while roasting.
I soak the cleaned seeds in salt water overnight in the fridge. Then drain, toss with a bit of kosher salt and seasoning, spread on a foil lined (or Silpat) cookie sheet. I roast at 275 for 15-20 minutes, till they get however toasted I want them. Just keep an eye on them, no matter what temp. They can burn very fast. No, I don't use any oil. Soaking overnight makes them nice and plump. I eat the whole thing, the shell is more fiber.
Seasoning - chipotle, pumpkin pie spice, cinnamon and brown sugar, use your imagination!