To make coconut oil soap, first, turn your crockpot on low.
Fill a medium-sized bowl with water and go outside with the lye, safety gloves, glasses, and long-handled spoon. Lye is extremely potent, as are the fumes, so do not do this in the house, and be sure not to breathe in any fumes.
Slowly mix the lye into the water, stirring gently. The mixture will quickly become very hot, so be careful! Let this mixture cool outside for 5-10 minutes.
Add the (liquefied) coconut oil to the low-heat crockpot.
Slowly add the lye mixture into the crockpot; do not let any of this splash onto your skin.
Stir the crockpot with a wooden spoon a few times, waiting for it to take on the consistency of pudding.
Cover your crockpot and allow it to cook on low for 45-60 minutes.
The final mixture should look something akin to vaseline, with a pH between 7-10. The heat will reduce the lye's alkaline nature, but if the pH reading is above 10, it is not done "cooking". You can test the pH with a pH strip, but allow it to soak for at least a minute for an accurate reading. The mixture should feel slightly waxy to the touch.
Add essential oils once the lye mixture is at the right pH level and stir briefly. Do not add them before the mixture is cool, or the scent will be lost.
Carefully spoon the mixture into your bread pan and allow it to cool. The coconut oil will harden rather quickly, so as soon as the mixture feels cool to the touch and relatively firm, cut it into soap-sized bars.
Place the bars on a rack in the open air, or somewhere with good air flow. Allow the bars to fully dry out and harden for the next few days, and then let them sit for 2-3 weeks before use.
Then, start lathering up and enjoy the impressive effects of your brand-new coconut oil soap!