They shot them into space, as implied in that hack episode where Harry's apparently ex- serious girlfriend comes back from the dead.
That's a prime directive violation.
Random cultures coming across sophisticated torpedo technology not to mention what they can figure out from examining an alien being, be it new medical advances or bio weapons. It's really not cool.
Those torpedoes are supposed to be shot into suns or planets so that they burn up and don't leave evidence behind.
In a shoddy episode of Enterprise before there was a prime directive, Archer said that after they died on a prewarp world, which is where they were being jailed at the time, that T'Pol would in secret systematically remove all proof that aliens had ever been on that world up to and including exhuming their corpses after they're dead and buried.
Kes was kept in a foot locker.
Caretaker was kept in a draw.
Hogan was turned into Scat and then picked over by Dinosaurs.
The Klingon Half of B'Elanna was picked over to graft DNA onto mostly human B'Elanna, but it's doubtful the mostly Klingon corpse was still in a draw somewhere since B'Elanna later agreed to have a bit of her brain cut out to give to the Doctor's sickly Vidiian Girlfriend, when they could have been a mostly completely intact fully Klingon B'Elanna in a draw somewhere.
They just powered on when Harry's corpse was dumped outside (in deadlock).
They lost a couple during the Killing Game and those crewmen would have certainly be taken away as trophies... It's surprising that Kathryn didn't ask for the polished skulls of her friends back when she was cementing her peace with the Hirogen.