We use clean and sanitized reused plastic bottles to refill with the products you order. The refill amounts are predetermined: 10oz, 16oz, 32oz or 128oz (1 gallon). Get 10% off when you purchase 1 gallon of any products (discount applied automatically at checkout). Prices include a charge of $0.99 per bottle that covers cleaning and sanitization costs. For more on the refilling process, please click here.