I can't even remember noticing the gunk...I delivered (with midwife present) my 2nd, 3rd, 4th and 5th babies and pulled them straight onto my chest.
I was so anxious to meet the little person who had growing inside me I didn't think of it.
The midwife wiped them down while they where in my arms.
If you really think it will bother you just ask them to wipe them down first.