If you don't have access to soap, you can still clean a plastic water bottle using alternative methods. Here are a few options:
Boiling water: Fill the bottle with boiling water and let it sit for a few minutes. The high temperature can help kill some bacteria and sanitize the bottle to a certain extent. Empty the bottle and rinse it thoroughly with clean water.
Vinegar solution: Create a solution of equal parts vinegar and water. Fill the bottle with this solution and let it sit for a few hours or overnight. Vinegar has mild disinfectant properties that can help eliminate some germs. Afterward, rinse the bottle well with clean water to remove any vinegar smell.
Baking soda: Make a paste using baking soda and water. Apply the paste to the interior of the bottle and scrub it thoroughly using a bottle brush or a clean cloth. Baking soda acts as a gentle abrasive and can help remove stains and odors. Rinse the bottle well with water after scrubbing.
Boiling or sterilizing methods: If you have access to a stove or microwave, you can boil the bottle or use a microwave sterilizing method to sanitize it. Check the manufacturer's guidelines for the bottle to ensure it is safe for these methods.
Remember, while these alternative methods can help clean a plastic water bottle to a certain extent, they may not provide the same level of cleanliness and germ elimination as using soap. If possible, it's always recommended to use soap and hot water for thorough cleaning and sanitization.