Adiós

There are several ways to say good bye in Spanish but only a few are appropriate on the streets of Mexico City. Here is a list by category.

Dorky:

• Adiós: good bye
• Hasta luego: So long
• Hasta pronto: id.

Slangy yet neutral:

• Baygón: from "bye" and the insecticide by Bayer
• Baik: from "bye" and "bike"
• Báilele: dance it, from "bye" and bailar
• Ahí la vemos: we'll see each other there
• Ahí te ves: you'll see yourself there

Picaresque:

• Te lo lavas: wash it (your butt)
• Te lo laballenas porque te apescadito, id. but more folkloric (notice the inserts whale and little fish to give a poetic tone)

Avoid:

• Hasta la vista-only native speakers can say it, with a Schwarzenegger accent
• Vaya con Dios-only native speakers can way it, with a John Wayne accent
  

Keep it real and stick to Baygón