Rubber Mask Grease is ideal for coating latex and foam latex due to its castor oil content, which protects the latex pieces. It also contains an oil content similar to your skin. Compare this to having the latex area look chalky as would happen if you had used ordinary creme foundation over untreated latex.
Note: Rubber Mask Grease is designed for use on latex appliances; it contains Castor Oil, which makes it perfect for latex appliances. If used directly on the skin, it will feel slightly heavier than regular creme foundation.