The night before the activity, pour 2 cups cold water into a mixing bowl. Sprinkle 8 packets unflavored Knox gelatin evenly over the water. Let it sit for a few minutes to absorb and soften.Note: If using boxed Jello, simply prepare it according to the package directions and skip the gelatin steps. Bring 6 cups of water to a boil. For firmer Jello, slightly reduce the water amount. Add food coloring to the hot water, stirring until you reach your desired color intensity.
Carefully pour the hot, colored water over the gelatin mixture. Whisk immediately and continuously for 1–2 minutes, until fully dissolved and smooth with no lumps.
Pour the liquid Jello into a sensory bin or baking dish. Add clean Valentine’s toys and trinkets. Refrigerate overnight until fully set.
Before playtime, add scoops, tweezers, bowls, jars or other sensory tools so kids can dig, scoop, and transfer toys.