The following information on sandblasting was sent to me by Jessie (1/15/06):

I love your website information on cast iron care.  I have read all the questions and answers, and I have only seen one entry on sandblasting the old pans.

Unfortunately I am officially old enough to have a lot of experience with cast iron and a lot of other things. Good thing I am a quiet guy or I would never shut up, trying to distribute my wisdom - heh, heh, heh!

I have a nice collection of cast iron ware that I have picked up mostly at second hand stores or yard sales. That, by the way is the most economical way to buy them. Since I don't know or trust where the pans come from or what has been in them, I always sandblast them. I have always worked where a sandblaster was available for the employees to use, so I always blast them clean and start over with the seasoning. You do get a more uniform look to the pan. 

There are different types of blasting media. Glass bead is finer and lest abrasive than graded river sand used by some. It does not matter much, just pay attention to what you are doing and just get it down to bare metal and call it good. You would have to be a moron to sit there holding the blaster tool for an hour in one spot and blast a hole right through the pan. My apologies to you morons out there! I usually cure at the warmer end of what I hear others have done. I do it at about 405 degrees F. 425 degrees F. also works well.

It is normal for them to smoke like crazy for an hour or so.  I always cure (season) a clean, shiny or new pan at least three (3) times before I start using it, The turning the pan upside down trick is best too, I believe.