I didnt even bother, they may have pissed and crapped all over insulation, but it's not like you can spell it, can you? plug up the gaps, set traps, kill all the vermin before replacing anything IMO. No use replacing stuff if they're just coming back in. If you see a gap, any gap, the size of a dime, plug it up. Go on your roof, get a ladder, the whole deal, no gap is too small for mice. Every single vent, every single entry, AC, deteriorated vents, etc. If you have a raised foundation, gotta address that as well, as they can be sneaking from the bottom to the top. It can be done, and I have like the worst conditions as my wife loves planting shit, which adds more access points and ways of mice concealing themselves. Sometimes you will have to patch from the attic to the outside, but that's life. No pest control will help you out with these things, but be diligent and you can get rid of them with minimal costs. be on the look for complicated roof joins, they can have a lot of small openings, those took me a lot of time to get completely right, but it is completely right at this point. Galvanized will delay the rust for several years.