The shelf life of margarine depends on a variety of factors, such as the production method, its sell by date and how it is stored.Margarine, also known as oleomargarine or oleo, is often used as an alternative or substitute for butter.or a long-term option, you can freeze your margarine for about 6 months while preserving its taste if you replace the wax rapper with foil or another freezer friendly product. Although salted margarine may last longer, we recommend you follow the same storage methods discussed above.