hey i got thru with scissors but wtf is that blackish bluish grennish bullshit in the rim and can it harm me

ps can i jus use one straw and jus use a hole for the airhole.
Porkchop913 Reviewed by Porkchop913 on . homade vap plz help i need to no why when i go to cut it y wont it cut thru on the metal Rating: 5