Going through my Dad's basement I found a few spark plugs. Looks like they are "New" old ones still in boxes. One is a Champion C-7 wrapped in Champion paper in its original box. The box also says C-7 Champion 18 MM 1" HEX. I also have two other identical Champion 7 boxes that say 18 MM 7/8" HEX. on them but inside are two different "New" old Champion 6-M and 6M spark plugs. I am assuming these two aren't in their correct boxes. And white porcelain upper parts of each spark plug are totally different from each other. All of these spark plugs have a black cardboard tube covering the "spark " part so I guess they are "New". Just wondering if anyone could use these?