I'll continue answering the questions so far before going on to glycerin (Eli, I will answer your question shortly - strangely enough I haven't done a proper post on jojoba oil!).
However, Q&A today comes from NappyRina who asks,
Q1: When using coconut oil as a penetrating (pre-wash/pre poo) treatment to avoid hydral fatigue during a wash, will it really penetrate if I have used sealing oils/butters (shea, castor, etc) since the last wash?
Without an actual experiment I can't say but I am pretty certain that coconut oil would get to the cuticle and penetrate. Why am I so certain?
Chemistry - Oils like shea butter and castor oil blend quite well with coconut oil. Since the oils mix AND MOVE, undoubtedly coconut oil will get to the cuticle surface and likely move into the hair.
I'm currently going diagram crazy, so here is a new way to think about your oil, not as a solid layer but rather as little clumps which can move around.
Q2: Are you using the same "finger tip (refresh here)" amount of coconut oil for the pre-wash treatment as when applying post wash & beyond or soaking your hair in oil like the traditional pre-wash treatment used by Indian women?
The fingertip tip (pun intended :)) is not for a prewash. For a prewash, I apply coconut oil like it is going out of fashion. The reality is I probably don't need to but my aim is to cover all my strands in as little time as possible. For daily styling I use much less oil and simply reapply as needed. I have tried to say I and my as many times as possible in this paragraph just to emphasize that I like to do this, others may not.