-Create a small house, put chess boards everywhere inside, but leave a space and one box. Place a fireworks shooter in the box. Make a door and tell the Sim to go in the room. Delete the door and tell the Sim to light a firework. Light another and repeat until the Sim is dead.
-To kill a Sim quickly in a fire, first make a 10x12 house. Count how many Sims you want to kill and add one to that number. Fill up the house with exercise machines and an amount of boxes open in a line equal to your number. Put a fireworks launcher in the end box of the line of boxes. Enable the move_objects on code and pick up the Sims you wanted to kill. Place them in different empty boxes in the house. Tell any one of the Sims to light the fireworks. If done correctly, once launched the entire house will catch on fire at the same time. Note: The game may freeze for a couple seconds. Also, you may run out of money while you are doing this trick.
-Place an unwanted Sim in a room, then get rid of the door and buy some fireworks. Light them off. They will go up, come down, light on fire, and kill the Sim.