Di I really need to clean my LP's?

Recently, when announcing to a relative my intent to use a recently purchased Spin-Clean Record Washer on some LP’s, of which I am the original owner and which have not been played in decades, her reply was, “If you’ve always handled them correctly, and stored them in their sleeves, why do you need to clean them?” I think that this is a very good question. Is there a good reason for me to clean them?