A request to a scan a software image for specified criteria is received, the software image comprising layers stored in a first data store. Metadata in a second data store, different from the first data store, is searched through to obtain information corresponding to the software image. A first set of the layers that matches the specified criteria is determined, based at least in part on the information. The first set of layers is marked as un-referenceable. Asynchronous to fulfillment of the request, a second set of layers of the layers to be deleted is determined, based at least in part on the metadata, the second set of layers including layers marked as un-referenceable, and the second set of layers is deleted.