Sealant is applied onto or into a folded-seam closure of a metal can. Instead of introducing sealant into the U-shaped lid flange and drying, according to the invention the compound or sealant is applied to the base flange, the base of the metal can being dipped into a current of fluid sealant or at least brought into contact with it at the surface. This substantially improves the precision of dosing and the exact amount of applied sealant.