Agree with Wizzard, Kettner and Pierce your propane is contaminated and you need to change suppliers. Try and set up trap as dougrainer is telling you. I have worked with propane for years , their should be no oil residue in the propane. After you use up that propane your tank needs to be dropped and cleaned. BE extremely careful working with propane it is extremely flammable and the liquid propane is extremely cold when released as a liquid ,sub zero temperature causing frost bite to exposed skin. Make sure you soap check all fittings looking for leaks.
