Anyone worked with severly sick/underweight ball pythons?

Seriously thinking about adopting another ball python... I have 2 currently that are not rescues, but I just started thinking about the ball python I saved a few years ago during college. He was severly malnurished and underweight. His tank was disgusting, but I took it and cleaned everything up for him. Unfortunately, I lost him in January, but I'd like to think I prolonged his life. He had an mazing personality too. What was the worst condition a snake was in when you recued them? How are they now? Just curious... I think I'm going to seek out some ball pythons in need of care in the next few months and take one in.