I've never had to deal with anything pitted as bad as
THIS.
What is the best way to prep this mess before priming? I'm going to do the best I can to get all the scale out from the pits, but there are umpteen million of them and I want to finish this door before the 22nd Century.
I'm thinking a good washing with phosphoric acid?
Any help will be greatly appreciated.
BTW, Sandblasting has to qualify as THE most boring thing I've ever done in my life. No wonder they charge so much!