A quick, cheap and easy way of getting rid of unwanted graffiti from the body and/or neck of your guitar. Because toothpaste isn't just for cleaning teeth anymore!
https://youtu.be/lt4VUXGehxo
as an FYI:
White toothpaste works better for cleaning things other than teeth due to the higher concentration of the micro-abrasive granules (that are embedded within the paste) when compared to the 'colored-gel' toothpastes. I often use white toothpaste to remove scratches from my eyeglass lenses, as well as for CD and DVD scratch removal.
Most of the time, simple finger pressure to rub the paste is all that is needed, but if you use a toothbrush, you want to use a
SOFT-BRISTLE brush and
not a HARD or MEDIUM bristle, otherwise the bristles can actually cause additional scratches, which is NOT good on your eyeglasses or optical discs.
However, for a completely NON-abrasive removal of supposed permanent 'magic marker' of the likes of Sharpie and Marks-A-Lot brands, a perfect solvent is also isopropyl alcohol, aka, 'rubbing alcohol', and some cotton balls to apply/remove it. Works like a charm every time for me.
Having said all that, the micro-abrasives in the white toothpaste should only lift a minimal amount of the clear-coat on the guitar when used as Jon has done, minimal as in 'microns' unless you scrub like with gorilla strength. So the toothpaste should not really harm the finish or even be evident after the fact, unless you know to look for it.
I never thought to use toothpaste to remove marker ink,
so good on you Jon and thanks for doing this demo and sharing this technique! 
:shaka:
Also, this almost makes me think of something that Dan Erlewine might show on one of the StewMac guitar shop repair videos.