Gone un-noticed by most, this term defines little piles of tobacco left by people who have "gutted" a blunt by removing all of the tobacco from the inside and (allegedly) replaced it with marijuana. Phillie guts are common litter at most gas stations, probably because that's where Phillies are bought.
Hey sombody must have been getting ready for a party... did you see that big pile of Phillie guts sombody littered in front of pump 4?
Hmm what do I do with these Phillie guts?
Put them in the cellophane of the blunt box and chuck it out the window!