Avocado turning brown ... here is some help...

I'll try the onion tip.

We usually squirt some lemon or lime juice on the exposed portion of the avocado with the pit still in place, and have had mixed results.

So the rumor is that the Mexican cartel (Knights Templar) is maneuvering to control avocado sales and production, as they are currently doing with limes. We need to preserve them well, because they are going to get expensive.