I've used half a quantum stockpile for this, i.e. a refuse stockpile feeding a mine cart on a track stop that dumps into magma (you can use a pit instead, and have a refuse pile at the bottom). There are two benefits to this:
- Your "dump" functionality isn't tied up to sentient refuse dumping.
- Dumping dorfs won't slip and fall down into the pit (has happened for me into magma).
The disadvantage with the refuse stockpile version is that it's very cumbersome to set up, since you have to manually select all relevant (= those you've encountered so far) sapient creatures as corpse, body part, and bones refuse subcategories (at least) in your sapient refuse stockpile (after first "excluding all" to exclude titans/FBs, which you may want to butcher), and then manually remove exactly those entries from the regular refuse pile.
Also, at a very late stage, you'll find that clown corpses are causing horror, considered sapient, and unspecifiable [i.e. belonging to the same hidden set as FBs/titans, and thus can be sent only to stockpiles that have not excluded all]. My end solution to the clown problem was to stop cleaning out the trap array (there was nothing of value to salvage anyway. Hair could be spun into thread, but the thread could not be further processed into cloth, which would have been cool).