Most ant-type insects are weak to fire.
Ants
Anything about ants! ๐
Go to a hardware store and get liquid ant poison, it's a gel with borax in it. Take small 2 inch squares of tin foil and place them all around where you find the ants coming into the house. Drop lots of drops of the gel onto the tin foil. Add more drops every day as the ants eat it up. If you have pets or small kids, you can make little covers to go over the tin foil with old boxes and cartons to keep the little ones from touching it.
This works even better if you can find the place outside the house where the ants are coming into the house. Leave lots of these traps along the trail of ants and it will kill the colony in a few days.
Thanks for this! We'll try it!
You can also buy traps full of the stuff that are already (mostly) kid-safe; you snip off the end of a plastic container and set out out. Be aware that there are different baits for different ant types, though. The other way works too, but for a little more money you don't have to mess with foil.
While you're waiting for the colony death, few ants will cross a line of ground cinnamon. You can shake a border around a room, and - unless they're coming up through the floor in the middle of the room - it makes a pretty efficient barrier. It's cheap, human-safe, and easy to vacuum up after the colony is dead.