Luckily we do have a very small bottle of peppermint oil (.125oz) we got when our kids had a lice problem from school. Not much left but I put a few drops on a few cotton balls and set them in the base cabinet where they seem to be coming from. The main drain pipe from the sink goes straight down through our concrete slab and I’m sure they’re coming in from there but I’m not sure from where on the outside. Too much snow here to even check. Hoping the oil and the cleaning makes them move out soon. We’re going to have guests next week.