Drain the pickle liquid into a large bowl, then whisk in the sugar and drink mix. Carefully pour the mixture back into the pickle jar. Refrigerate the pickles, shaking occasionally, for 2 days before eating. The pickles keep, covered in the refrigerator, for 10 days.
For red pickles, use cherry or red tropical mix. For green pickles, use blue raspberry mix. For purple or black pickles, use grape mix.