What can I use to kill the weeds but not my pets?

I have weeds coming up between the bricks on my patios and walks. I do not want to use chemicals because of my dogs, cats and the natural wildlife that hang out around my house. What can I use that will kill the weeds but not the pets?What can I use to kill the weeds but not my pets?boiling hot water - pouron when pets aren't around - reapply several daysWhat can I use to kill the weeds but not my pets?Rock Salt. No iodine kind though.What can I use to kill the weeds but not my pets?Lay black plastic on it for several days. The heat and lack of water and sunlight will kill the weeds. No chemicals needed.