BORAX aka 20 Mule Team (in the laundry soap aisle)is a great killer of carpenter ants. Kills slugs too! It's a natural resource from the desert and you can kill off a nest of carpenter ants with it, and I imagine perhaps sugar ants too. It also reduces the spider population in your home. We used it when we had a nest of carpenter ants get into our house.We sprinkled it around the perimeter of our house outside and my husband placed it along the sole plates under the house. The adult carpenter ants are pretty tough and at first it may not seem they will get killed off by it, but their death is delayed long enough to take the powder back to the nest, and you end up killing off the entire nest. It's cheap, non-toxic and a much better solution than dangerous chemicals, which costs hundreds of dollars if a professional comes in. Borate is a derivitive of the same natural resource and often is seen as an ingredient in insecticide type of products. I've never tried this but I've also heard it can be sprinkled on carpet to kill fleas and flea eggs and then you vacuum it up!
Thanks to Tammara for submitting this household hint!