I have a friend who owned a tackle store for a while and he would by bulk plastics. To keep them fresh he would put them in smaller bags and once in a while add a drop of cooking oil to them to keep them from drying out. When he closed down the store, I bought all of his crappie stuff so now I have several thousand jigs that I keep the same way. Inside an airconditiond room, oil once a year and they will keep for a long time.