Over time, the slider (the piece that locks the teeth of the zip together) starts to loosen and gape. Rather than writing the zip and the product off, here are a few simple steps to try to mend the zip:

1. Reach for a pair of pliers.
2. Push the slider to the end of the zip, making space for the pliers.
3. Use the pliers to gently squeeze the top and bottom plates together.
4. Be careful not to press too hard as the two plates can break apart so take your time.
5. Try out the zip slowly to check if it has worked. If not, return the slider to the original position and try again.
6. Put some Vaseline or lip balm on the zip so it moves more smoothly.