I'm wondering if it's possible that there are 2 types of pins. Most people say that they are easy to see and easy to eradicate but that is not my experience and it seems that more and more people are having trouble getting rid of them.
From what I see, mine are tiny and they look a bit thicker than the photos I've seen. Mine are almost impossible to see by eye and I need to use a magnifier to be sure of what they are.