Much like Eye Bleach, it is the only cure to when somehting so terribly awful stains your gray matter. Used when Eye Bleach, and steel wool are just not d*mned good enough.
Ingesting massive amounts of alcohol, resulting in inability to remember events after ingestion. Experienced brain-bleachers will later try to piece the night's events together by looking at sent texts, talking to friends, etc.
Guy 1: Dude, remember when you started a fight club last night across from the cop shop? That was awesome!
Guy 2: I wish I did, but i blacked out. Everclear is brain bleach for me.