We use UPS Ground to ship our Food Grade Hydrogen Peroxide.  UPS requires a street address for delivery.  So, even if you're the creative kind and enter the street address for a  Post Office they are not going to deliver it.That will get your package sent back to us and incur a return shipping fee.  Nobody wants that.  So please provide a valid shipping address.If your order does not contain Hydrogen Peroxide we can ship by USPS to a P.O. Box.