One runs across the liquid bluing bottles fairly often but this one is better than most. It has a nearly complete label and has a lot of the original liquid in it. The reason for the liquid bluing is so that once white clothes don't turn into that ivory color seen in vintage clothes. Otherwise one would look like Lt Colombo. Now blue dye is in almost every laundry detergent so there isn't much need for liquid bluing.
The Quick Elastic box has an image of a sad iron on it so I am thinking it is from the days. The box has never been opened and is in excellent condition. Could be a bit newer than I think. Based on the graphics on the back I am thinking 40s or 50s.