What can I do if I start to feel like the cap has loosened up?

Since our caps are made of plastic, they will crack or deform when exposed to strong external pressure, making the cap feel loose. If it loosens up, the nib can become dry even when the cap is closed. In that case, even if you try refilling the marker, the ink would not be absorbed. If that happens, we recommend to replace a cap with a new one.