The other effect that grunge guitarists used was one of the most low-tech effects devices, the wah-wah pedal; it is one of the rare pedals that requires no external battery or AC mains power and it uses very simple circuitry.
Both "[Kim] Thayil and Alice in Chains’ Jerry Cantrell..great advocates of the wah wah pedal." Guitar feedback effects, in which a highly amplified electric guitar is held in front of its speaker, were used to create high-pitched, sustained sounds that are not possible with regular guitar technique.
Whereas metal guitarists' overdriven sound generally comes from a combination of overdriven amplifiers and distortion pedals, grunge guitarists typically got all of their "dirty" sound from overdrive and fuzz pedals, with the amp just used to make the sound louder.
As well, VH1 writer Dan Tucker points out that different grunge bands were influenced by different genres.
Grunge guitarists "flatly rejected" the virtuoso "shredding" guitar solos that had become the centerpiece of heavy metal songs, instead opting for melodic, blues-inspired solos – focusing "on the song, not the guitar solo".
In Will Byers' article "Grunge committed a crime against music--it killed the guitar solo", in The Guardian, he states that while the guitar solo managed to survive through the punk rock era, it was weakened by grunge.
The positive way that grunge bands viewed stompbox pedals can be seen in Mudhoney's use of the name of two overdrive pedals, the Univox Super-Fuzz and the Big Muff, in the title of their "debut EP Superfuzz Bigmuff".
Other key pedals used by grunge bands included four brands of distortion pedals (the Big Muff, DOD and BOSS DS-2 and BOSS DS-1 distortion pedals) and the Small Clone chorus effect, used by Kurt Cobain on "Come As You Are" and by the Screaming Trees on "Nearly Lost You".
Robert Loss acknowledges the challenges of defining "grunge"; he states that one can recount stories from the grunge scene to try and explain it, but as soon as you try to define grunge this way, "it slips out of your hand". Cross defines "grunge" as distortion-filled, down-tuned and riff-based rock that uses loud electric guitar feedback and heavy, "ponderous" bass lines to support its song melodies.