Step 1: Materials
1 natural agglomerated cork (made from many small pieces of cork adhered together)
1 pair of earphones
1 awl or small phillips head screwdriver
1 felt tip marker
1 serrated knife
*1 xacto knife (optional)
if you aren't sure whether or not you have the right kind of cork, this is a great resource:
Step 2: Mark
The "mouth" can be used as a guide when making the bottom marks.
Step 3: Poke
Step 4: Cut
Test the slots to make sure they hold your earphone wire. If too small, carefully carve out the slot to make it a bit wider.
*An x-acto blade may be used here to clean up your cuts.