Subject: What is the coefficient of friction of human skin?

When I place a coin on my forearm, I can tilt my arm to quite a steep angle 
before the coin begins to slip. Scientifically, this implies that my skin 
has quite a high COF (coefficient of friction). However, repeating this 
mini-experiment with different materials will yield different results. 
Also, what are the contributing factors that make someone's skin more or 
less "slippery"? (Eg. gender, age, race, weather conditions, body hair??)
yours-in-waiting,
Edwin

Re: What is the coefficient of friction of human skin?