Purchased several years ago and used a few times, then stored in a drawer with other dishes. Before listing, I washed it again with dish soap. [From Marna's product description page] Ideal for washing narrow-mouthed containers such as plastic bottles, barley tea pots, milk cartons, bottles, and water bottles. Simply put water and this product into the bottle and shake to clean the inside. Important notes: ・Do not use for anything other than its intended purpose. ・Depending on the plastic bottle, it may be difficult to remove the product. ・Keep out of reach of small children. ・If the balls inside break, stop using and dispose of the product immediately. ・Do not use on items with mirror glass, such as thermos bottles. ・Avoid using chlorine-based (alkaline) bleach. ・The color may dull depending on the usage conditions, but this does not affect the quality. ・After use, rinse thoroughly, drain, and store in a well-ventilated place to dry. ・Do not place near fire.