how to get the cool screaming sound with the guitar

hey, i really need to know how to get the squealing sound guitarists use sometimes to start songs off and stuff. the best example i can think of is the start of 86 by green day. i thought it was either mutin the strings or jus sliding down, but it sounds way wrong. help me guys!

If it's an early Green Day song I can garentee that there'll be a high amount of gain (which I'm sure you already know). The most common way of getting really high squealling from your guitar is to use your pick against the strings and slide that down.
Instead of holding the pick so the wide faces are looking to the floor and celing, turn is so the thin side is instead. Next, place it the gap between two string, usually the E and A before finally sliding it down across the fretboard.
This is a great way of squealling, although I'm not sure if it's actaully what you're after. Try, if not, them I'm stumped...anyone any other ideas?

it could be, but i dont think so. Im not sure if i explained it very well to start. It almost sounds like left hand damping, which sorta then turns into a kinda high pitched roar. to start i guessed it was jus moving the chord up and downa few frets, but it sounds too dam good. anyone whos listened to the intro on 86 will know wot i mean (i hope).

I really dont have much clue about wot im talkin about when it comes to these little tricks!

hey.......me think i know wat ur talking about..it sounds like a high pitch harmonic.

use a electric guitar with distortion.Then place ur pick on ur index finger and put ur thumb over it.U must try picking the string and muting it with ur skin....it might sound complicated but one u get the hang of it,it is easy.
if u still fail ,make sure ur pick is in the position and instead using the pick to pluck, try picturing using the skin beside the thumb to pluck...ô¡ô