Welcome aboard. Soda blasting is a nice way to go if you can get a yard to allow it. I had the bottom scrapped clean at a yard two years ago.( 4 weeks and a lot of money) This yard would not allow blasting which would have cut my costs by a lot. The history I was told that sand blasting had been allowed at their facility at one time and when they ended up being sued for screwed up paint jobs from the blasting the practice was stopped. If you have a yard that allows it use this method.