1) Bad music.
These three categories cover the types of material that are toxic to the ears and minds of those that are unfortunate enough to come into contact with them. The best way to deal with it depends on which category you have been exposed to.
For category 1, locate tracks by Stereophonics or Muse, press play, crank it up to 11 and take a deep breath.
For category 2, pass the gossip along immediately, thus forcing it to exit your mind.
For category 3, get drunk and fuck someone immediately.
"I was getting a lift with Josh, but I'll be taking the bus from now on, due to the massive dose of Prince related ear poison he pumped into the car"
"Yeah, I heard about it, and I already passed that ear poison on, so I'm immune to your injection. Move it along!"
"Right, that's our weekly shot of ear poison done with until next sunday. Now let's go to Foxies and get us some whores!"