One of the easiest ways to add flavour and succulence to food before barbecuing is to marinate. Food can be marinated for a few minutes or up to several hours, and even overnight. The longer the marinating time, the stronger the flavour will be, so don't marinate delicately flavoured foods like fish for too long - 30 minutes is usually sufficient. At least 3 hours is recommended for marinating skinless chicken (12 hours with skin), and to really tenderize beef or lamb, 8 hours to overnight is ideal. Food should be refrigerated while marinating but brought back to room temperature before cooking to achieve optimum flavour. Leftover marinades can be brushed over food while it is cooking, or heated and served as a sauce, but make sure always to boil the marinade for at least one minute before serving. Because many marinades have an acid-based ingredient, it is best to marinade food in shallow nonmetallic dishes. Heavy-duty plastic bags are also good for marinating foods. Prepared marinades can be stored in screw-top jars in the refrigerator for up to two weeks.