Object are created such that each of the objects stores a bit that designates eventual removal of one of the objects. Further, the objects are added to a data structure that includes a set that comprises a union of a plurality of subsets such that each subset in the plurality of subsets is stored separately according to a corresponding thread and such that an added object that is added to the set by a given thread is stored in the corresponding subset. In addition, one of the objects is logically removed, without physical removal, from the set by activating the bit. Each subset is periodically swept. All objects marked with the activated bit are physically removed.