Okay, so I read that this is supposed to clear out "all" headstones in the mausoleum, but it doesn't do that for me. (in this case that's fine)
I don't really want it to remove them all either, but I've noticed it does delete SOME of the headstones?

I had a panic-moment a bit ago when I hit "cleanse the dead" by accident and clicked "yes" Interesting thing is, when I initially chose this option the mausoleum said I only had a few animal headstones and one townie...and it did remove all of those, but then when I went into "manage the dead", most of the towns dead were still there, ie; the main town's people and active family's loved ones etc all were all still listed as being in the mausoleum.

Does anyone know how this option is supposed to work and how is it that, thankfully, I didn't remove my towns history of dead folk?

As long as the dead sims have Descendents they won't be deleted or shouldn't be deleted. The only ones that would be deleted are those that have no Family Tree or the Family Tree has come to a dead end.

Hey, I know this thread already got its answer, but can I borrow it for one question?

Can I safely delete pets' gravestones from the mausoleum? It's so full and I don't really need or care for the animal ones, they can go entirely for all I care. However, could it be an issue if they have living descendents, just like human sims? And if yes, and those graves shouldn't be deleted, is there a way to clean up only stones and urns of pets that have no linked family trees and are therefore safe to kick out?