The invention relates to an oleaginous mildew and corrosion-inhibiting composition, and the use of said composition to protect metal from corrosion and mildew. The composition comprises, in parts by weight, from about 20 to 60 parts of an oleaginous material such as a lubricating oil, 10 to 40 parts of organic solvent, 20 to 60 parts of corrosion-inhibitor consisting of a sulfonic acid-carboxylic acid metal complex or a mixture of said metal complex with a small but effective amount of an oil soluble alkyl phosphate, from 0.1 to 2.0 parts of an oil soluble antioxidant, from 0.0 to 5.0 parts of a water-displacing compound, an effective amount of a mildew-inhibiting compound, and from 0.0 to 1.0 part of a heterocyclic metal deactivator.