Oldtimer, I started in Nov. and finished in mid Dec.
I tried EasyOff oven cleaner first and it didn't seem to do the job to well. I ended up using a torch and scrapper to do the job. Just worked on it about and 1and 1/2 hours a day. After I'm done with my tubs I'm going to go through rags and Kerosine or Brake cleaner to get off the residue. Then I'm going to Sand Blast everything before painting the undercarriage with Zero Rust. I am using a specialized scrapper that enabled me to get 99.5% of all areas. I'll take a picture of the scrapper later on and post it on this post. I'm pretty sure you can get it at any hardware store.