Abstract: A disposable sleeve for a container including a liner having inner and outer surfaces; a housing coupled to said inner surface of said liner with said housing defining a pocket and an opening to access said pocket; a heating element disposed within said pocket; and a cover disposed over said opening and coupled to said housing to enclose said pocket, wherein said cover is at least partially removable from said housing to uncover at least a portion of said opening and to enable activation of said heating element to generate heat upon exposure to air.