The Pre-Motor Filter ensures that dust and debris do not reach vital components of the EyeVac, and that clean air is returned to the environment. The filters for the EyeVac are designed to last the lifetime of the unit. As users, we understand that sometimes filters become accidentally damaged and offer replacements for your convenience. To clean, simply use a soft brush to clean away excess particles, then wash gently with water and mild soap. Let sit 24 hours to dry completely and reinsert into the unit. Do not soak in water.