either wood filler or a plumbers epoxy lay it in and sand away and repeat until you get the shape back apply epoxy good as new most of the time.Plugs with wooden lips I prefer wood filler to keep the weight closer to the original,epoxy can get heavy an throw off the action on those type of plugs.Another tip using epoxy is to not sand it any finer then 150 grit because anything finer will not allow the epoxy to grab property resulting in a crack and also sand lightly in between coats.Make sure the plug is free of dust at all times wearing vinyl gloves to keep the oil from your fingers off the epoxy or you get the famed fish eye.