Place steaks in a large shallow dish. Combine soy sauce, brown sugar, pineapple juice, vinegar, and garlic salt. Stir well and pour over the steaks. Cover and marinate for 4 hours in the refrigerator, turning occasionally.
Remove the steaks from the marinade. Grill over hot coals for about 5 minutes on each side, or until done.
Servings: 6