An air cleaner comprising a housing including a surrounding housing-wall defining an open interior; an inlet arrangement; and an out-let arrangement; the inlet arrangement and outlet arrangement being at opposite ends of the housing; the housing defining an access opening in communication with the open interior; a cover removably secured to the housing over the access opening; the cover having an exterior surface and an opposite interior surface, the interior surface facing the housing open interior; and a cassette-free filter cartridge removably oriented for selective removal within the open interior between the inlet arrangement and outlet arrangement; the filter cartridge including a media pack having opposite inlet and outlet flow faces; the media pack comprising a plurality of flutes extending In a direction between the inlet flow face and the outlet flow face; the media pack being closed to air entering the inlet flow face and passing outwardly from the outlet flow face without filtering flow through media of the media pack; and a seal member secured to the media pack; the seal member forming a releasable seal with a sealing surface in the housing so that the filter cartridge is in sealing engagement with the housing; the filter cartridge including a cartridge-handle sized to accommodate at least a portion of a human hand; and the air cleaner characterized in that: (i) the interior surface of the cover includes a receiver that contains at least a portion of the cartridge-handle when the filter cartridge is operably oriented within the housing interior and when the cover is secured over the access opening; and (ii) the cover is pivotably secured to the housing by a hinge arrangement and the cover further includes a projection arrangement extending from the interior surface of the cover into the housing open interior, when the cover is secured over the access opening; the projection arrangement being between the inlet face of the filter cartridge and the housing surrounding wall to help hold the filter cartridge in sealing engagement with the housing; the projection arrangement includes at least first and second legs (645, 646) extending from the interior surface of the cover; and the receiver is between the first and second legs and laterally spaced therefrom; the first and second legs (645, 646) extending about 5-30% of the length of the inlet flow face. (i) the interior surface of the cover includes a receiver that contains at least a portion of the cartridge-handle when the filter cartridge is operably oriented within the housing interior and when the cover is secured over the access opening; and (ii) the cover is pivotably secured to the housing by a hinge arrangement and the cover further includes a projection arrangement extending from the interior surface of the cover into the housing open interior, when the cover is secured over the access opening; the projection arrangement being between the inlet face of the filter cartridge and the housing surrounding wall to help hold the filter cartridge in sealing engagement with the housing; the projection arrangement includes at least first and second legs (645, 646) extending from the interior surface of the cover; and the receiver is between the first and second legs and laterally spaced therefrom; the first and second legs (645, 646) extending about 5-30% of the length of the inlet flow face. the projection arrangement being between the inlet face of the filter cartridge and the housing surrounding wall to help hold the filter cartridge in sealing engagement with the housing; the projection arrangement includes at least first and second legs (645, 646) extending from the interior surface of the cover; and the receiver is between the first and second legs and laterally spaced therefrom; the first and second legs (645, 646) extending about 5-30% of the length of the inlet flow face.