My parents have a two-story house in Michigan. They have a carpenter ant (large black ants) problem in-between the first and second floor. A couple weeks ago a plumber was in the second floor bath to replace a leaking toilet seal. When the toilet was removed, a large mass of ants fell out from under the toilet – it was a huge party…drinks and munchies were (on) the house. Evidently, they had crawled up through the rotted area around the toilet drainpipe. A lethal dose of RAID! was administered. The problem – carpenter ants continue to appear on the first floor. Any suggestions on how to extract all the ants without a full house fumigation or removing the first floor ceiling drywall? A small section of drywall on the first floor below the leaking toilet was removed (water damaged), but there are no signs of ants here. (Limitations – my mother has outlawed the further use of RAID or similar chemicals)