Now that we're on the subject of seasoning.
My mother taught us to season CI with Crisco and I used it for years. Now, I prefer flax seed oil available from stores that sell vitamins and supplements. I think it makes a smoother seasoning.
Edible flax seed oil is called...you guessed it...flax seed oil. Flax seed oil that isn't suitable for human consumption is called linseed oil. Go figure.
Here is another vote for flax seed oil. I have used cast iron for a long time and never payed much attention to what I seasoned the pans with. Once they have a good base coat, it usually doesn't take much to keep them seasoned. A friend of mine gave me a 20" pan that he poured at his shop. It was a beautiful pan, but it was hard to get a good base coat that would stick. When he gave it to me he told me he had seasoned it with PAM, which I think was the cause for much of the problem. Finally had a friend sandblast the old coating and started over from the ground up.
Initially I put the pan in the oven on self clean overnight, that got rid of any residue. Cleaned and wiped it out with water and dried it on the oven burner. When the pan was warm and dry, I coated the pan with flax seed oil, wiped as much oil off as I could and put it back in the oven. It was baked it at 500 for an hour and then the oven was turned off as it sat in there for two hours cooling. It was the best coating I have ever seen on a pan. It almost looked like teflon. I repeated the heat, coat, wipe, bake, and cool process several times and was very pleased with the results.
As was previously mentioned, flax seed oil has the same chemical make-up as linseed oil, which is used to harden oil based paints. I will never use anything else to get a good base coat for a CI pan again.