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.
Place the baking sheet in the oven. Roast the potatoes for about 20 minutes. Then turn them over using a spatula or a pair of tongs. Roast for an additional 20-30 minutes, depending how browned and crispy you like them.lace the baking sheet in the oven. Roast the potatoes for about 20 minutes. Then turn them over using a spatula or a pair of tongs. Roast for an additional 20-30 minutes, depending how browned and crispy you like them.