There are some ocean front/view platinum weeks and even a few gold ocean front/view weeks that you could probably sell for more on your own. Also included are event ski weeks and some platinum ski weeks.
Most everything else you will get more going through Marriott's brokered sales than selling it on your own. They offer buy backs that are pretty quick and easy but unless you have a week that won't sell, you are better off getting on the list for the brokered sales.
Tracey S.