This subject has probably come up before - but I want to re-visit it.

Imagine that you are in a hurry and you need to make a quick note. So you just write the message on the skin of your hand or wrist. It's simple, practical and you know you won't lose it.

This technique used to be used by EMT's when they applied certain treatments to patients. For example, you put a tourniquet on a victim at 11 am, and you want the doctor to know this. You write on the patient's skin ... "TK applied at 11 am."

So here's my question?
What is the best kind of pen to use for this? It's possible that somebody has come up with something better than a standard ballpoint. Also, is there a pen that writes well on skin, but the message can also be erased fairly easily later?

And one other thing - what if the person's skin is black and not white. Is there a pen that shows up better for dark sin?

thanks,
Pete2