H.P.
I have a few of them in different sizes. I use soap, but I don't leave it sitting in water or leave water sittign in it. I give it a good scrubbing and wipe it dry. Then, I set it on the fire and use a paper towel to rub oil into it like lotion. The key is to make this process a quick one. Don't wash it until you are ready to go through the whole process, which doesn't take five minutes.