Please kindly erase the teeth stains by the front side and please be a litlle gentle, not brush too hard. The white melamine sponge itself will gradually wear and tear,and become thinner and thinner during cleaning. It is the nature of melamine sponge. It's normal phenomenon. It is safe, effective and no hurt enamel.
It is easy to open as long as you bring the product with the logo side up, as below image showing. It is very important information for you to open and please make sure open the handle based on the “ lever principle”.
1. Open the fixture 2. Insert the new refill 3. Fold the sponge 4. Close/Clamp fixture