Abstract: A vapor-absorbing insert for hot food 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 a food container lid. The insert is manufactured by staging and stacking the several layers of cellulosic material in an assembly machine and then pressing them 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 perorations which intertwine fibers between adjoining layers, after which the bonded layers are cut to shape. In use, upon peeling off the release layer, the element self-adheres to the underside of the food container lid.