Heat the frosting in the microwave for 30 to 60 seconds or until pourable.
While this is melting, in another bowl, whisk together the powdered milk, ginger, cinnamon, cloves, and nutmeg.
Add the molasses and melted frosting to the dry ingredients.
Slowly add cornstarch and oil, alternating between the two, until the slime is thick and pulls away from the sides of the bowl.
Turn out on waxed paper for playing.
If the slime is too sticky, add additional oil. If the slime sticks to hands, use wet hands to play. Playing on wax paper is recommended.
Note: The powdered milk will create texture. Blend in a coffee grinder, food processor, or blender until a fine powder forms to create a smoother slime.