If the United States truly wants to apply the maximum pressure its strategy calls for, then Washington should move quickly to cut Tehran’s polyethylene exports, especially those to China. As a first step, the U.S. Treasury should reiterate that polyethylene imports are prohibited, and should add to its sanctions list the Iranian companies that produce the chemical. Despite the blanket industry sanctions, the majority of Iranian petrochemical companies are not on the list. Next, Washington should discuss with China and other importers how they could find alternate sources of polyethylene. If China demonstrates a willingness to cooperate, the U.S. can follow the precedent it set regarding crude oil, whereby it facilitated a transition to new sources of supply by issuing temporary waivers that approved the continuation of imports at a reduced level. If Chinese firms resist – as some of them have in the case of crude oil – Treasury should punish them to demonstrate that a failure to comply has significant costs.