The disclosure concern air cleaners. Preferred air cleaners are shown which include a housing and a removable and replacement primary filter cartridge. Optional and advantageous features are shown. An optional mechanical interlock, operated with a non-threaded, movement of the cartridge, is provided between the primary filter cartridge and the housing. The preferred primary filter cartridge is conical in shape. A preferred optional safety or secondary filter cartridge is shown. Preferred methods of assembly and use are provided.