Makes sense to me as well, no oil. Wash it and dry it well (blow it out with a aircompresser if you have access to one) and then the first run will make grain-dust that will keep everything from rusting. I would do all three as close together as possible. From then on I would just blow it out with a aircompressor, right before I used it to crush some grain. I personally would only blow it out once every six months or so. That's just me, though.