NOT finding the rat that has died in your house. The smell of a dead rat is something you are not likely to forget anytime soon, no matter how hard you may try. Preventing rats from entering your home in the first place is the best thing you can do to avoid dead rat smell.How to keep rats out.Rats and other rodents are creatures of opportunity.he smell of a dead rat is something you are not likely to forget anytime soon, no matter how hard you may try. Preventing rats from entering your home in the first place is the best thing you can do to avoid dead rat smell. How to keep rats out.