The LAPD bomb squad was called in and took possession of the explosive devices. The rounds were taken to another location to be detonated and destroyed, officials said.
The family was cleaning out their garage when they found the two large mortar rounds in a corner of a top shelf they had never looked at before.
"They said that if somebody hits it hard enough, it will explode," Veraporn Wongskhaluang said. "All the time, in 30 years in this house, we did not know."
The bomb squad cleared out the neighborhood as they removed the devices.
The family thought that they were toys until their son went to the house Saturday morning. The former Army soldier knew right away what they were and just how dangerous they could be.
"I took a look at it and almost fell flat on my back because I used to work with unexploded ordnances with the Army," Julian Navarro said.
"When I took a look at it, I was like wow, those are 81-mm mortar rounds and they're still live with the fuses and the timing mechanism still in them," he said. "I ended up telling my dad, we need to clear out of this garage and we called the LAPD right away."
The LAPD was called at about 10:30 a.m. Saturday.
The bomb squad was called in and it was then determined that the bombs were still active.
Sand was delivered to keep the devices from shifting around while transported to a location where they were to be dealt with.
The family said they believe the previous owner of the home collected them.
Authorities will be able to trace them back with the serial numbers on the rounds to figure out where they came from.