Several green glass bottles recovered from the wreck of the <i>Zuytdorp</i> (1712) in 1988 were extremely weathered and iron stained. Scanning electron microscope/energy dispersive x-ray analysis and thermal analysis showed that the hydrated outer layer of glass had suffered a calcium loss of approximately 21%, and water represented 41% of the total mass of the glass. Treatment of the exfoliant layer with calcium acetate solution was successful in redepositing Ca²⁺ ions into the weathered layer. Exfoliation of the degraded layer was overcome with a treatment combining the calcium acetate solution and an emulsion of the copolymer polybutylacrylate/polymethyl methacrylate, Primal AC-235.