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.
(Always use a baking sheet with sides for roasting vegetables.). 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.Sometimes I leave them in the oven even longer.oast 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. Sometimes I leave them in the oven even longer.