Yep! I caught that too. Stu cleaned his knife like that after the Billy “death” fake-out. Future Ghostface copycats have been doing it ever since then.
-Spoiler Alert:- Ok so you're... Ethan Kirsch (Ethan Landry), Quinn Kirsh (Quinn Bailey) or Wayne Kirsh (Wayne Kirsh) (The people who are the Scream 6 Ghostface and Richie Kirsch 's family) EDIT: I don't care, if I get killed or not because I am truly a fan of the Scream Franchise