I used to think old people were stupid for stuffing money under the mattress instead of in a bank account, but I can see where they were coming from now...
Bingo. LOL.
Be careful where you hide it. My wife's co-worker told her he stuck a thousand dollars in a book on his bookshelf. A couple years later he donated some old books to a bookstore that resells them. Yup, you guessed it! By the time he realized his mistake, the book and money was gone. Get a home safe, bolt it down, and keep it hidden from casual view, like behind a false wall.