"Keep it on Wax" was a phrase used by the band Alexisonfire. It was written to express their feelings towards their former drummer, Jesse Ingelevics(2001-2005).
1 - An expression of bad blood/beef through music or poetry. The intended response is that the issue will not spill over to people who have no knowledge in the subject. Or, moreover, keep the issue silent from unrelated parties.
2 - An old gang term thought to have a similar meaning. Instead of resorting to violence the parties involved, respectively, try to resolve the issue peacefully. Presumably also through a form of music or poetry.
"Hey, you and your girl need to keep it on wax. I've got my own problems. I don't need to be dealing with yours too."
Directly related to the saying "Write it down on stone" or "Written in Stone".
It refers to something that will most likely change. Something written in stone is permanent, whereas, wax can be melted down and appear as being brand new.
Travis: Wow, we're going to be best friends forever.
Zachary: Keep it on Wax, brother.