Abstract: A vapor-absorbing insert for non-ventilated delivery containers comprising a first and second layers of highly absorbent cotton fiber, and a third absorbent layer (which faces downward toward the food) having an applied layer of adhesive protected by a removable release layer which, when removed, exposes the adhesive for contact with the underside of the lid of a non-ventilated delivery container. The insert is pressed into a continuous laminated composite strip. The several layers may be bonded by pressure-induced interaction between the fibers of adjoining layers, and/or by adhesive fusing at their peripheral edges, and/or by spaced perforations which intertwine fibers between adjoining layers, after which the bonded layers are cut to shape. In use, upon peeling off the peelable anti-stick sheet, the element self-adheres to the underside of the food container lid.