This article proposes un/making as a designerly response to urgent environmental issues. By focusing on the simultaneous constructive and destructive aspects of design, this effort attempts to challenge design's dominant focus on making new things. The implications and potentialities of un/making are explored through a designerly inquiry into ongoing and emerging attempts to ban the plastic straw. Based on this inquiry, the article proposes an approach to un/making that is driven by speculative, what if questions, informed by the history of the plastic straw: from coming into being to becoming preferable and now emerging as a matter of concern. Through a series of speculative design artifacts, the authors articulate matters at stake in the un/making of the plastic straw. They also show how these matters are a stake in the un/making of disposability as part of a preferable future. Rather than proposing one preferable future, the article highlights the frictions that emerge in un/making.