Berryman B-60 HIGH-MILEAGE FUEL SYSTEM REJUVENATOR (part #7516) is not intended for use as anything but an in-tank fuel additive for gasoline engines. For cleaning the throttle body, we recommend using AIR-INTAKE & THROTTLE BODY CLEANER (part #2209) or B-12 CHEMTOOL CARBURETOR, CHOKE & THROTTLE BODY CLEANER (part #0117). For a piston soak, we recommend using B-12 CHEMTOOL FUEL INJECTOR CLEANER (part #0116), which can also be added to the cold crankcase at a rate of 1½-2 fl oz per quart of oil.