Review (1/5): Not sanitary.
Reusable seems like a good idea but keeping a clean one on hand for daily use is not convenient. I washed the volcanic ball with dish soap (grease cutting) & warm water but some oil residue remains, as proven by the discoloration. Even soaking in boiling water didn't rid of the oily smell.
If you have oily skin, the ball will quickly become saturated & rendered useless. The one from Revlon probably has the same issues. Stick to blotting sheets.