Well I'm no expert... been in the hobby for 1.5 years, but I found nassarius snails, pods, and blueleg/scarlet hermits (to a lesser extent) to be very good at keeping my sand clean.
Nass snails dig themselves into the sand and burst out during feeding time... their constant burrowing, feeding, and movement at night keeps the sand bed pretty well clean. Pods diet provides a natural solution as well, but they are hard to keep in a DT due to the fact that they quickly become a prime food source for alot of fish. Scarlet/bluelegs like to scavenge on the sand from time to time, but don't count on them on their own (they also will make meals out of snails occasionally).
Anyway look into nass snails they are good dietrius cleaners.