Pitt
I have commented on mouse nests before. Please be extremely careful when cleaning out these nests. Mouse "poo" carries the hantavirus. This virus can be fatal and it is transmitted through the air. So when you stir things up during cleaning be sure to wear a mask to prevent airborne transmission.
It can happen. I was recently reading a thread on another classic car site and the poster related a story how one minute he was cleaning a mouse nest out of his classic car and by the end of the day he was in the hospital fighting for his life.