Aaaaggghh! Last year we went through a period when ants kept appearing on my desk! It's in a spare room at the front of our house, in front of window. We scrubbed desk down and I sprayed lemon and water / vinegar and water along the front of the house. We never figured out where they were getting in or why but they eventually went away.
So today we got back from a few days away and so far there have been SEVEN ants on desk this evening. Really can't spot where they are coming from - window is closed, it's away from front door and they keep appearing on desk or window sill. How do I stop the little beggars? Presumably these are just the scouts but I can't seem to find where they come in to block.