Hi @Billyb, taking apart and cleaning a Plantower laser counter is possible. The following link will take you to an online tutorial explaining this process: https://publiclab.org/notes/kkoerner/09-17-2018/how-to-open-and-clean-a-pms-5003-air-sensor.
The other option would be to look into laser counter replacement. The bottom of the Sensor Maintenance article will explain more.