Many times concrete holes need water in order to ensure holes are completely cleaned. Use this water attachment in place of the air-control valve.
Always use the Vortabrush water attachment to clean holes that have become damp or wet. The “brush and flush” action of the Vortabrush attachment will remove the “paste” that coats the inside of the drilled hole. Use this water attachment in place of the air-control valve. Never try to clean a wet hole using just the air-nozzle attachment.