I imagine people are getting sick of this question around here. I've read many a post on this forum about steel plates and bought myself a 1/4" thick plate last weekend. I'm hoping to use it Wednesday for a bake and have been washing it with soap and water and rubbing it down dry with paper towels. There's no visible rust, and the amount of greasy/sooty junk coming off has dramatically reduced, but if I rub the surface with a paper towel applying moderate pressure, there is noticeable dark material coming off of the plate.
I've read many times here that mill scale does not need to be removed for safety, but have also read a lot of conflicting recommendations about cleaning practices (soap and water, sanding, vinegar/acid baths, etc.) as well as removal of mill scale. I'm not looking to remove the scale if I can avoid it, but I would like to not have particulates coming off of the plate, as I know it would freak out my girlfriend.
Just how clean is clean enough? How much time have people had to put into getting their plates clean enough? I've probably scrubbed this one with paper towels for a total of an hour and a half or more of actual contact and spent another hour of contact with it under soap and water.