I am interested in getting an electrostatic air filter for our central air system. I see that yours are supposed to last a lifetime, but only have a 5 year guarantee... How do you clean them? DO you clean them? I would be placing it in a slot for a 20"x30"x1" filter. There are all kinds of air filters designed for multiple purposes. Electrostatic air filters are unbeatable in quality, function, and duration. For a high quality electrostatic air filter, consider the Pleat-A-Static Air Filter which can be made to fit your 20” x 30” x1” size specifications. They can be cleaned with regular soap and water or there is a special cleaner for them as well.