my kid broke my Swiffer handle, so I designed a new one.  

printed it with PLA-CF for the added strength.  I cut the model vertically and then printed it in two halves so the layers are length wise.  for a smaller printer I printed it diagonally in my print bed.  Then I used super glue to bind the two pieces together.  

It fits in the existing handle like a glove and my kids used it and approved it.  so far its still going strong.