Wasp Yellow Jacket Nest In Wall. If your nest was killed a month ago you should have noticed any odor by now. While wearing protective clothing drill a small hole in the wall as close to the nest as possible.
Use caulk or a similar sealant. If they have a spiral shape they may be hornet nests. This would help you to track its nest.
When a wasp nest is fully established inside of a wall the secretions from the nest will soak the drywall and as the colony gets bigger the sheet rock will be degraded to the point where the nest has the ability to come through the wall.
A yellowjacket nest is at its highest capacity in mid to late summer. Yellow jackets in wall german wasp or german yellow jacket. If there is a noticeable odor deodorizing agents can be injected into the wall void. Yellow jackets have been getting inside my house for the past month most likely from a nest in the house wall.