There is the "Limit Past Posts" feature under the privacy settings. It doesn't delete your stuff, but it does make it less visible. Not ideal, just a start. Go

There is the "Limit Past Posts" feature under the privacy settings. It doesn't delete your stuff, but it does make it less visible. Not ideal, just a start. Go to "see more privacy settings"... then look for 'Limit the audience for posts you've shared with friends of friends or Public?'. It will present a "Limit Old Posts" button.