In a heat-proof mixing bowl, combine the lemon gelatin and 1 cup of boiling water. Stir continuously for 2 minutes or until the gelatin crystals are fully dissolved.

Stir in the 2/3 cup cold water (or reserved pineapple juice), lemon juice, and salt until well blended.

Place the bowl in the refrigerator for approximately 45 to 60 minutes, or until the mixture reaches the consistency of unbeaten egg whites.

Gently fold the drained crushed pineapple and grated carrots into the thickened gelatin using a spatula until evenly distributed.

Pour the mixture into a 4-cup gelatin mold, individual ramekins, or an 8x8-inch glass baking dish.

Refrigerate for a minimum of 4 hours, or until the salad is completely set and firm to the touch.

To unmold, briefly dip the bottom of the container in warm water for 5 seconds and invert onto a serving platter; otherwise, slice into squares and serve chilled.