We had a bunch of really tiny ants in our bathroom. Put down a little dish of mixed borax and sugar - they picked out all the sugar near the surface and then stopped coming. Then tried borax, sugar, and water. They ate it up, the dish was completely surrounded by ants, and then the next day there were no ants at all.
At a former home, we used to get a trail of tiny “sugar ants” leading from the back porch into the kitchen, and from there–elsewhere. Once I had an ant climbing along my glasses frame–while I was wearing them(!).
After disposing of them, I Windexed their path, especially inside & outside the back slider & windows. End of the problem for that season. They need to follow a scent trail.
Costs about $3 and works great indoors and outside.
Another homemade solution is to use the borax with sugar and water, and dip cottonballs into the solution. I read long ago that soaking the solution in cottonballs prevents it from drying up if just sprayed on floor.
Borax, sodium tetraborate, mixed with sugar will kill ants. It also can kill pets, children, etc. Powdered borax can also be used to kill roaches and other bugs if sprayed under baseboards, in cupboards, etc. The roaches get it on them when powdered, and that kills them. When it cakes up it is not very effective. When mixed with powdered sugar and/or cooking oil, it is ingested by the bugs and poisons them.
V.J.V. - but keep out of the reach of pets & young kids, yes
Yes, it works. It is just the DIY home version of Terro Ant Killer which is a mixture of sucrose (sugar) and sodium borate (Borax). Here is the SDS for Terro. Bottom of page 2.