I got a boa off craigslist once, I didn't even know if I wanted him but he came with a tank even dirtier than that one so I knew I had to take him. He had an RI from the poor conditions, cleaning him up and raising his temps was all it took to cure that.
Once I get back to work I plan on having a custom enclosure build for him because a 55gallon isn't nearly enough floor roof.