my trick for old truck was Brake Fluid. Put some Brake Fluid on a paper towel and rub it in really well. Then wipe of with a dry rag.
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01 2500 Sport. 2wd, 4" MBRP straight pipe w/ RBP 18" tip, leveling kit, auto trans. AEM Brute Force. Now runnin w/ 2 stroke oil, And an Edge Juice w/ Attitude.