How to Wash! 5 Ways to clean a copper water bottle. 1. Vinegar with salt 2. Baking soda with lemon or vinegar 3. Lemon and salt method 4. Clean the inside of a copper bottle using salt and lemon or vinegar and salt 5.Go traditional with tamarind ✔Take a combination of salt with lemon juice or salt with vinegar, use whichever product is available at home readily. Take the mixture, add a little water and pour it inside the copper bottle. Close the lid and shake the bottle vigorously for a while, then throw away the contents and wash the copper bottle with water.