Co-production is a risky method of social inquiry. It is time-consuming, ethically complex, emotionally demanding, inherently unstable, vulnerable to external shocks, subject to competing demands and it challenges many disciplinary norms. This is what makes it so fresh and innovative. And yet these research-related risks are rarely discussed and, as a result, risk-reduction strategies remain under-developed within training and research processes. It is for exactly this reason that this article draws upon Mary Douglas's notion of "social pollution" in order to understand the tensions and challenges of co-production. It seeks to expose the generally hidden politics of co-production.