Stir well, with a spoon, until the mixture is wet and crumbly. Make sure that there aren't any dry spots.
Fill the silicone molds with the salt mixture and pack it down. Fill the molds tightly, like you would a sand castle.
You can also fill Dixie cups to make little sand castle structures.
Allow the salt sculptures to dry overnight.
Step 3: Unmold the salt sculptures
To unmold the Dixie cups, flip them upside-down. The salt sculpture should come out easily, but you can squeeze the sides of the cup gently to help it come out.
To remove the salt sculptures from the silicone molds, carefully push up from the bottom of the mold and gently pull the salt sculpture out of the mold.
Set the unmolded salt sculptures onto a baking tray or other flat surface that can handle food colouring.
Step 4: Mix up the food colouring
Add about 1/4 cup of water to small bowl or cup. Prepare 1 bowl for each colour you'd like to paint with (eg. 5 bowls for 5 colours).Then add 5 - 10 drops of food colouring to each bowl.
Stir the food colouring and water until mixed.
Step 5: Have fun painting your salt sculptures
Use an eyedropper to squeeze drops of "paint" onto your salt sculpture. Then watch the color spread across the salt.
Add a second, and even a third, colour to your salt sculpture. Silicone molds with ridges allow for some colour separation, but generally the colours will start to blend where they meet.
Continue adding colour to your salt sculptures. Experiment with colour mixing and abstract patterns.Allow the salt sculptures another 12 hours to dry before handling them.