I think an interesting question is "do black holes only increase entropy?"
Taken from Wikipedia on the definition of Hawking Radiation (http://en.wikipedia.org/wiki/Hawking_radiation) , "...rotating black holes should create and emit particles.â This implies that a black hole must have an angular momentum associated with it in order to emit Hawking Radiation and thus a higher entropic state.
Now, let us take a classic example, a celestial body interacting with a black hole. For the purposes of argument, let us theoretically allow the planet to be at maximum entropy. That is, there is no useful energy in the system to allow for interaction. We will take the black hole to have a high amount of entropy, perhaps because it has not interacted with any matter in a good while.
By the conservation of angular momentum (since we discussed the black hole has to have angular momentum to emit Hawking Radiation), the matter from the celestial body will not simply be devoured by the black hole, but accumulated on what is known as an accretion disk (http://en.wikipedia.org/wiki/Accretion_disk). Summarily, the accretion disk is transference of matter from one celestial body to a stronger gravitational brother (i.e. the black hole) whereby matter is siphoned from the less dense object to the denser object. The matter on the accretion disk is accelerated and becomes superheated through friction; in the process, X-rays and other forms of radiation are emitted.
Basically, we have gone from two high entropic states (inert planet and a black hole with little interaction) to a lower entropic state, because the energy in the planet was changed from a useless, uniform state, to a volatile state.