We consider contest success functions (CSFs) that extract contestants' values of the prize. In the case in which the values are observable to the contest designer, in the more-than-two-contestant or common-value subcase, we present a CSF extractive in any equilibrium; in the other subcase, we present a CSF extractive in some equilibrium, but there exists no CSF extractive in any equilibrium. In the case in which the values are not observable, there exists no CSF extractive in some equilibrium.In the case in which the values are observable and common, we present extractive a CSF extractive in any equilibrium; we present a class of CSFs extractive in some equilibrium, and this class can control the number of active contestants.