... material:Nylon and PE making it reuseable.Just fill in the warm water and cleaning agent,shake again ... best bottom,making it stand up well when fill in the water.4.Foldable:Can be rolled,folded ... :How to clean this Collapsible water bottle?Answer:Fill in the warm water and Cleaning agent,then shake ... 10 times,then fill in the clean water to shake more times.Question ...