ENGINE OIL -- Formula 1 Brand 4.55 Liters (1 Gallon) Engine Oil ?

I Have Two Cans Of Formula 1 Brand 4.55 Liters (1 Gallon) Engine Oil 20W50 Viscosity In Garden Shed For A Few Years. I Believe They Are Still Usable. Price Is 8 For One Can And 14 For Both. I Think They Are Suitable For High Mileage Older Cars. Ideal for flushing out your engine before putting in good expensive oil into your engine.