The Rodent Exclusion process can be extremely difficult. A fully-grown rat only needs to find an opening the size of a quarter to get into your home, and sometimes that small opening is not somewhere easily found. It is also important to use the correct materials when you seal up entry points. Using expanding foam or shoving steel wool into a hole is not sufficient to seal that opening. Lastly, the Rodent Exclusion process will usually require time and multiple inspections. Even if you are successful in sealing an entry point, the Rodents may find or make another way in.