I walked into the living room and found Lizzy with the vaseline jar. It was all over her hands, clothes, hair, and couch. I could not believe my eyes. (This is a picture from another episode.)

Morgan washed her hair TWICE with normal baby shampoo. I think this achieved nothing but distributing the vaseline evenly throughout her hair.
I washed her hair for the third time that night with hand soap. Her hair still felt slimy and looked like it was wet.
The next morning I looked online and decided to try peanut butter. After a few goops I realized that crunchy peanut butter wasn't going to work. Elizabeth didn't appreciate the exfoliating property.

Luckily the missionaries had some creamy peanut butter, so we continued the fourth washing. It helped a little bit.
That night I did another peanut butter wash, but I was much more generous with the peanut butter. =) This fifth washing worked pretty well.
We followed up with a sixth washing - normal shampoo - careful not to get it in her eyes. This time her hair turned out rather normal looking… normal as in "not washed after a dose of yogurt" normal.

Lizzy hates getting her hair washed. But after the seventh wash with normal baby shampoo she was nice and clean. If you don't count the yogurt, that is.