All you have to do is use a pliers to pull off the larger colored end like I have shown above. You do have to get a good grip and pull REALLY hard. You will not break them, it goes right back in and snaps closed when you are done!
When you get the top off this is what the inside tube will look like. You just take your re-inker bottle and put a bunch of drops of ink right in the hole in the center and let it soak in.
Take the tube out fully so you can re-ink both end for the small and large tips. Once you have inked the center, put it back in and pop the marker end right back in, it goes back in with a click. This works great!! It takes a few minutes after you are done for the color to soak back up to the ends but then its just like having a brand new marker again!
This is great for the retired colors if you still use them and did not buy extra markers or just for the colors that you use a lot!!