10. What if I see residue build up in my liquid lines? Customer Service February 25, 2020 15:27 Updated Follow This may indicate that the lines are not being purged after each use. Please refer this question to Service-Tech-Team Support Center. Related articles 11. Can I buy or use a longer extension cord? 6. Why should I purge my device after each use? 14. What is the correct PPE to wear while using the ByoPlanet® Electrostatic Spray System? 4. Can I spray inside or outside? 1. How many square feet will one gallon of approved product treat?