MAC Volcanic Ash Thermal Mask ($20 for 100ml) is a limited edition mask that came out with the MAC Style Black collection. I recently found it sitting on my bathroom shelf still untouched and immediately put it to good use. I used it for about twice a week for a month.
Booyah Mask Face! The mask comes out of the tube oily, grainy, and muddy. I mixed it with some water then applied to my face, it heats up upon touching my skin but the sensation wears off quickly. I leave it on for about 10 minutes then remove it in a circular motion to get the grainy stuff work its exfoliation thang. The mask gets extremely messy during the removal process so its best to rinse off in the shower. My skin didn't feel too different afterwards but the warming sensation experience was nice. Its a fun mask to have but not a necessity.