You can just keep it on there and rub it off with a cloth before use. Keeps the whole batch from rusting. Or yeah Dawn dish soap and water will take it right off. I bought about 2,000 5/16 steelies and actually sprayed a little Balistol down in the jar I keep them in just to keep the rust away. When it comes to steel, oil is your friend. They do go a little overboard with that shipping oil though. I think if they come from overseas it helps a lot. That and for shelf life. Whenever I get a tool from overseas the first thing I do is clean that crap off and just put a light machine oil on it.