Step 1: Materials
What you'll need for this project is a "fat" highlighter and some pliers
Step 2: Ink
What you'll need to do is remove the smaller piece of ink out of the highlighter using the pliers
Step 3: Capping the Ink
What you'll need to do next is remove the cap on the back of the marker by grappling them with the pliers then remove the bigger piece of ink out, next you can throw both ink pieces out you only need the cap for the back and front and the bare marker
Step 4: DONE!
Now all you'll have to do is put what u want to hide in the marker and then put the cap back on then you're ALL DONE!