CANCELLATION FEATURE FOR PHARMACEUTICAL WASTE DISPOSAL ASSEMBLY

A cancellation feature (2203) for a pharmaceutical waste disposal assembly (10) having a first surface (2201) and a second surface (2202) can include a first cancellation member (2204) that is secured to the first surface (2204) and a second cancellation member (2205) that is secured to the second surface (2205). The second cancellation member (2205) automatically moves from a pre-engaged configuration that allows engagement with the first cancellation member (2204) to a post-engaged configuration that inhibits engagement with the first cancellation member (2204). The automatic movement occurs after engagement and/or during disengagement between the second cancellation member (2205) and the first cancellation member (2204). The first surface (2201) can form a portion of a receiver that receives pharmaceutical waste, and the second surface (2202) can form a portion of a receiver retainer that retains the receiver. Conversely, the second surface (2202) can form a portion of the receiver and the first surface (2201) can form a portion of the receiver retainer.