Methods, systems, and apparatus, including computer programs encoded on computer storage media, for automatically cleaning a portion of an environment. One of the methods includes detecting movement of a person within a physical environment; determining that one or more threshold criteria for cleaning at least a portion of the physical environment are satisfied; detecting one or more areas of the physical environment with cleanliness levels that satisfy a threshold cleanliness level; determining that the portion of the physical environment for which the threshold criteria are satisfied likely was insufficiently cleaned; and in response to determining that the portion of the physical environment for which the threshold criteria are satisfied likely was insufficiently cleaned, sending an instruction to a device in the physical environment to cause the device to present a notification that identifies the portion of the physical environment that likely was insufficiently cleaned.