Another strategy achieves the self-healing in thermoset matrices by incorporating meltable thermoplastic additives. Common cheeses used for topping are American, Swiss, and other meltable cheeses. MeltDose works by incorporating a drug substance with low water solubility into a "meltable" vehicle. Meltable versions are used to make quesadillas. One mechanism is a small meltable pellet that holds down a spring.