Help! Staining on Gris?

[AlexM.]

Having trouble with staining on bottom of skillet. This was heavily crusted as shown, yet wonderfully preserved as its in great shape minus this blotchy state. E tank for most of it then used over clean cycle to take off some stubborn crud spots. Planning to go back to E tank to see if that works, yet thought I'd ask for some ideas. Pics are after oven and steel wool/soap cleaning - it's an xmas gift so I'd like to get this baby gleaming. Thanks. Ps is that a C or G?

 

[Doug D.]

Crud that has been reduced over time to just carbon is not going to be budged by lye. Electro would be the next thing to try to get it to release. If it is down to just black stains, straight vinegar and steel wool can often remove or at least minimize them. If it is stains remaining from removed rust, a product called Evapo-Rust is said to work amazingly well.

I'd say it's a C, but the dashes are unusual.

 

[AlexM.]

Great thanks for the tips. E tank to start and go from there. I just remembered that I used bar keepers friend on a prior skillet dark spot and while it took it off, after washing with soap and water and seasoning that spot & a small trail ended up with a browner/dark brashing seasoning. Iswore it off but perhaps if I put it back in E tank for a little after... I'll try vinegar first , thoughts on BKF? don't think it is from rust but who knows under all that crud.

 

[Doug D.]

When working with straight vinegar and steel wool, you will get streaks where the straight vinegar runs, but just go over them with the steel wool as well and they will even out.