The purge tool is a syringe that fits specifically into the Evolv Spray Gun Applicator’s fluid coupler nozzle. Fill it up with water and then purging the water pushes out any residue or dried solution that may be stuck inside. By using the purge tool after each use, you can ensure that your airbrush gun stays clean and ready for the next application. Like any other spray gun applicator, it needs to be cleaned regularly to avoid clogging and maintain its performance.