To get rid of ants you can dissolve 1 teaspoon (5ml) powdered boracic acid and 10 teaspoons (10ml) sugar in two cups of water (50ml). Soak small cotton wool balls in this solution and leave them near the trail of ants. They carry the cotton wool back into their nests and the whole colony can be wiped out.
Alternatively, you can sprinkle a couple of drops of water where you have boiled some lavender on the path of the ants. Very soon, they will have disappeared. You can also boil leaves from a walnut tree and wash the areas where ants frequent.