Best way to reduce dwellers in my vault

I know that there's a way to kill your dwellers. If they die in a disaster. You can revive them or let them remain dead. After 24 hours they will disappear.

But this may have some negative side effects as your other dwellers will be sad about the dead people lying around.

So my main question is, what is the best way to kill your dwellers.

Background: You only can have 200 dwellers in your vault and a waiting queue of about 10 dwellers waiting at your vault door. If the wait queue is full you won't be able to open lunch boxes anymore. This will prevent me from opening my lunch boxes.

If I reached those limits, I need to kill my bad dwellers. Which is the most efficient method? Should I rush a room until rad roaches occur and kill my bad dwellers without any weapons and need to wait 24 hours and loose happiness? Is it better to send them to the wastelands without weapons and let them die? Will this also reduce the vault happiness too?

The times I have had the need to "off" a dweller I just send them into the waste and let them die there. You will have the option to "remove" them once they are dead.

Just remember to send them out without any outfit or weapon.

Release 1.3 now allows you to evict Dwellers.

In the 1.3 release, several new features were added, such as pets, new "pickup lines", and the ability to evict Dwellers, as well as a few other small features.

To evict a Dweller, all you need to do is drag them out to the wasteland, and on the panel used to give them Stimpacks and Rad-Aways before sending them out to explore, is a little red icon; when pressed, will evict the Dweller. Removing them from the roster entirely.

Quick and easy.

Disclaimer: Prepare for feels. The only thing stopping me from hating myself entirely every time I evict a Dweller, is the lack of sad violins playing as they leave the vault.

Rushing a room will eat dwellers much faster than sending them into the wasteland for two hours, and though it only affects 6 dwellers at a time, you can feed more and more dwellers to the 'death room' as they begin to die off. Plus, there's always that ~25% chance that you'll actually get a fresh batch of resources. Either way, once removed, they won't affect happiness.

put an elevator down 2 levels and build the cheapest production room leaving a space so that it inset touching any other room besides the elevator. then rush the room until it fails. it will kill off the dwellers in the room but the fire/rad roach/mole rats will not spread to any other room in your vault. once you have an excess of caps you can also use this to put all of your storage rooms and livening quarters at the bottom of your vault.