A boy rubbed chocolate on/in his hair.
I am not sure if we say "the chocolate is on/in his hair"
If "the chocolate is on his hair", then we "wipe the chocolate off his hair".
If "the chocolate is in his hair", then we "wipe the chocolate out of his hair".
But normally, we use "wipe on a surface" and I am not sure if hair is a surface.
Some suggest to say "clean the chocolate out of his hair" but I couldn't find any structure "to clean dirt/things out of something" in dictionaries
or "wash the chocolate out of his hair" but we didn't use any water, so the action can not be "wash".