What was found
MKE - WHEN LANDING GEAR WAS RETRACTED ON TAKEOFF, DOOR WARNING LIGHT REMAINED ILLUMINATED. THE GEAR WAS CYCLED, BUT THE INDICATION REMAINED THE SAME. UPON ARRIVAL AT TOL, MAINTENANCE INSPECTED THE MLG DOOR AND FOUND THE LANDING GEAR DOOR STRIKER AND SWITCH DIRTY. THE SWITCH AND STRIKER WERE CLEANED AND LUBRICATED, AND OPS CHECKED PER DC-8 MM 56-60-01. ALL WAS NORMAL, AND THE AIRCRAFT WAS RETURNED TO SERVICE. (X)