just clean it...let it soak in some water and simple green then rinse it out from inside out then let it dry.

 

If it is K&N it should only be cleaned with their recommended cleaner. We are talking about very thin layers of linen. They may be specially treated also.

Better choice might be an AEM or Amsoil universal fiber technology filter. These are long life filters that do not need reoiling. Oil not being the best thing IMO because of the close proxmity of the mass air sensor. Both companies offer them in several cone filter sizes. AEM has the most sizes.