As the Church participates in God's Mission, how is it called to oppose evil forces in the world? In the last fifty years, spiritual warfare approaches have come to the attention of evangelicals through missionary encounters with spirit cosmologies of the global South and the rise of Pentecostalism within World Christianity. But Janet Warren's book, Cleansing the Cosmos (Wipf and Stock, 2012), offers a theological and practical alternative to spiritual warfare, one that emphasizes God's cleansing of space in his creation, with evil not so much a strategic enemy but chaos that seeks to intrude over God-given boundaries and contaminate what God has made holy. This article analyzes Warren's proposal and explores how it may help in some areas of mission where spiritual warfare approaches have been problematic - namely in relation to exaggerated God-Satan dualism, discontinuity of local religious forms, and controversies over space.