A Core deposit is a form of deposit you pay until returning your old part. If you don't have the core at the time of purchase, you must pay the core charge. That charge is refunded to you when you return the core.
Every time you step on the gas, you may be subjecting your engine to power-robbing deposits and friction. Unlike most fuel additives, Gumout All in 1 can provide complete fuel system cleaning and lubrication protection.