Refrigerator Cucumbers - or other things

This is a refrigerator vegetable recipe that marinades vegetables in a brine.  Once in the brine mixture, they can be stored up to two weeks.  This recipe says it is for Cucumbers, but feel free to mix it up with zucchini, cauliflower, carrots - any vegetable that you enjoy pickled.

      4 lb Cucumber
      1/2 cup md Onion
      3 c  Sugar
      3 c  Cider Vinegar
      4 t  Canning Salt
    1/2 T  Mustard Seed
    1/2 t  Alum

Cut cucumbers into 1/4 inch slices and onions into 1/8 inch slices - combine in a large container.  In a large pot, combine the remaining ingredients and stir over low heat until sugar is dissolved.  Pour over
cucumber mixture and mix well.  Cover and, when cool, refrigerate overnight.  May be kept up to 2 weeks.