It's pine tar, plain and simple. He had it on for sure in 1 other game in the playoffs and at least 2 other games in the regular season. Even though he washed it off it still has the desired effect - have you ever gotten tree sap on your hands? That s*** takes days to come off.
Not to mention Kenny is having the greatest post season pitching run in the HISTORY of the game - that's a lot of years and a lot of good pitchers. And that coming from a guy who has normally been BLOWN UP when pitching in big games.
So yeah, pretty obvious he's cheating. I guess I don't mind so much since most of the hitters are pumping HGH anyway.