There is an innovation by the Rebbe, based on the approach of the Alter Rebbe, whereby it should be stated in the contract for selling Chometz to a non-Jew that the sale includes utensils which have visible Chometz in them, and it is not necessary to immerse them in a Mikveh since the non-Jew does not intend to use them even though they are in his possession. (Refer to Likutei Sichos,18:8) In this case also, the non-Jewish merchant does not intend to use the utensils even though they are in his possession, because he wants to sell unused utensils, so we do not have to dip them in the Mikveh.