Acid and Copper Solution. 1  1. Ensure that the metal you are working with will rust. 2  2. Measure some hydrochloric acid into a plastic bottle. 3  3. Dissolve a bit of copper in the hydrochloric acid.  4. Dilute the copper and acid solution with 1  water. 5. Clean your steel or iron thoroughly.  6. Apply the acid 1  solution. 7. Allow the metal to  rust.
Quick Answer. Depending on size, potatoes should bake in the oven for around 50 minutes to 1 hour. Flipping the potatoes every 20 minutes during the baking process helps to ensure consistent baking throughout the entire potato. Continue Reading.
Rub the entire potato with olive oil and kosher salt. Prick with a fork three or four times to allow steam to escape while baking. Place potatoes directly on the oven rack and bake at 400 degrees for about 50 minutes, depending on the size of your potatoes. I start checking the potatoes at about 40 minutes.lace potatoes directly on the oven rack and bake at 400 degrees for about 50 minutes, depending on the size of your potatoes. I start checking the potatoes at about 40 minutes.