My cat is a retard

Once in a while my cat will find some toy that I bought her months or even years ago. I have no idea where she comes up with these things. Like today, she was playing with this little toy catnip mouse that I think I bought her for Christmas like 3 years ago. I haven't seen the thing in years. I keep my house really clean. I just don't know where she hides these things. How come I don't find them when I'm moving furniture to vacuum or something? She is like a magician.