Nibbles, 6.5 bytes (13 nibbles)

|$/.=~$$>2$:

|$/.=~$$>2$:
|$              # filter each word int the input by
    =~$         #   group the letters by
       $        #   themselves
   .            #   and for each group   
        >2      #     remove the first 2 elements
  /             #   now fold over all groups
          :     #     appending them together
                #   (so if there is at least one letter
                #   present >2 times, the resulting 
                #   group will have nonzero length)