Lead is a through drier & is always used with cobalt &/or manganese. Lead drier improves the drying time of double boiled linseed oil & yields very pale & clear boiled oil.
Lead in combination with cobalt & calcium are suggested, particularly for long oil alkyds lead is the most important drier. However some of the problems connected with lead driers such as Sulphur staining & reaction with polybasic acids are overcome by inclusion of calcium drier. As lead is toxic in nature its usage in toys & edible film packaging is to be avoided.