2. Facial clay masks can adsorb and absorb sebum, toxin, bacteria, and viruses. They give short term effects (cleansing, tightening/lifting) and long term effect (increasing collagen, regulating sebum)

3. Clay is negatively charged. Therefore, when clay contacts with WATER, it activates the charged ions to become charged hydrospheres, which are the magnets attracting impurities, dirt, oil, and toxin. These are removed from the skin when the clay is washed off. In addition, swelling clay (like bentonite) will contract after evaporation and create suction pulling out blackheads/impurities to deep cleanse pores.
In conclusion, clay masks NEED WATER  (full hydration) to activate and gain these wonderful purifying/detoxifying actions.
-I always mix it, then let it hydrate completely for 5- 10 mins (non-swelling clay) . For highly expansive clay (like bentonite) 15-20mins.

Anhydrous clay masks (oil/wax based without any water added), which are easy to make because it needs no preservatives, unfortunately don’t have these benefits  because of the lack of ionization, swelling, and contracting. Adding too much oil to clay masks also compromises the clay’s cleansing power. In these cases, clay just acts as a thickener/gentle scrub or purely for marketing purposes.

4. pH of some clay is very high (such as bentonite is 8.5-10.5), it’s best mixed with acidic liquid like apple cider vinegar, or aloe vera juice. And check the pH of the final mix.

5. For blackheads, spots, and acne, it is recommended that clay and water should be mixed and applied at warm temperature .

6. Don’t let clay masks dry completely. They will suck out all moisture and good oil from skin. Usually 5-10 mins is enough for it to do the magic

Note: These are based on both scientific research papers and my chemistry/biochem knowledge.

This is all shared Info / research from my friend , Lam Dang