I remove the blade from the razor, rinse the blade off in running water, then dip the blade in 70% isopropyl alcohol (aka 70% isopropanol; rubbing alcohol). IME, the blades last a little longer than without an isopropyl alcohol dip. I haven’t tried the mineral oil trick, but that seems to work fine for some folks.
ETA: I usually get 4 shaves per blade, sometimes more.