Use the adjective hoary to describe something that is old and worn out — like the hoary jokes your great uncle Albert clings to.
The word hoary can also be used to describe something that is white or gray with age. Santa is usually depicted with a hoary beard and hoary hair, although sometimes mall Santas have to fake this with wigs and artificial beards. Hoary can also mean covered with white down — "The hoary leaves felt like velvet to the touch."
