We were warned before we moved into our new apartment that there's an ant problem. So it came as no surprise that within a few days we saw the little pesky creatures making their way across a wall. Instinctively we reached for a paper towel and liquid hand soap -- it happened to be Avalon Organics lavender -- and wiped down the wall. We haven't seen any ants since.
However, while researching this dilemma (we refuse to use pesticides), we found all sorts of eco-friendly suggestions.
Since we can't find the nest to pour boiling water on it, we're more drawn to the tips that involve sprinkling products on the ant trails. Some of these are: aspartame, black pepper, borax, catnip, cayenne pepper, chili powder, cinnamon, crushed mint, cucumber, a mixture of baking soda and powdered sugar, or citrus peel and water, or white vinegar and water. If the ants return, we think the idea that we'll try is to spray peppermint or spearmint essential oil on the trail.
You can find more information on Buy Organic, The Frugal Life, and The Dollar Stretcher. And there was an Open Thread on the subject on AT:NY last year.