Oatmeal (Ultra-Fine) can certainly be incorporated into a mousse-textured formula. However, because this specific grade of oatmeal is processed into an ultra-fine powder designed to disperse smoothly without graininess, it will not provide the physical "scrubbing" sensation typical of traditional exfoliants. Instead, it acts as a skin-soothing and moisturizing agent (colloidal oatmeal).

To create a mousse scrub using this ingredient, you can follow these guidelines:

1. Mousse Base: Use a foaming agent like Sulfate-Free Foaming Base to create the lather and mousse structure.
2. Soothing Benefit: Add Oatmeal (Ultra-Fine) at 1-5% to provide anti-inflammatory and moisturizing properties. It should be dispersed in the water phase; using heat at 70-80°C helps it disperse smoothly without clumping.
3. Exfoliation: Since the oatmeal itself is too fine to provide a scrub feel, you should add a physical exfoliant such as Camellia (Tea) Seed Scrub to achieve the desired scrubbing effect.
4. Preservation: Because oatmeal is a natural nutrient, it is critical to include a robust preservative system in the formula to prevent microbial growth.

This combination will result in a "Treatment Mousse Scrub" that both exfoliates and deeply soothes the skin.