as our talking before, it's just happen with us, we show this problem to you, we don't know whether our customer know this expense happened with them or not, if you want to check with customers, we will ask them to check their previous shipment happened this cleaning charge or not. I don't think customers will agree to pay this kind of expense if they know it happened. As you and us knew already, it's unreasonable charge, why it may happen.
PLEASE HELP TO AVOID THIS KIND OF CHARGE HAPPEN IN FUTURE ANYMORE.