From the front tip of the mouthpiece. It should amass into a blackish but if you spread it on something like a paper or your fingers it will be more golden. I think the black comes from plant matter in it (happens with my Arizer Air stems, gold wherever herb isn't lol). On the Grasshopper it wont really be found anywhere else, the inside chamber always comes out clean, and the screen seems to only amass herb around the sides, not as much oil until it gets to the cone tip.
I don't use what I get because it gets a little gunky with fur or pocket fuzz.
I think I'm the only one who has a completely spare mouthpiece... I'll look into maybe trying to disassemble it. I am afraid to break something though