Hard to say from the photos, might just be tarnish although it looks really thick like paint or glue. You have a well worn common date Buffalo with some sort of substance on the surface that is not pretty to look at, it would cost you $50-$60 to grade and slab a $2 coin. If you want to remove that gunk you could try placing the coin in some pure acetone for a few minutes to see if whatever is on the coin will dissolve away. Either way it will never be worth the cost to have graded and slabbed, many (most) old coins are not worth the cost.