The only secret like success I've had with homemade guac was using saran wrap like
RemydeHaviland suggested. I made a batch and left the extra in a container. EXCEPT I placed saran wrap snug against the top surface and the next day it was just about as green as when I'd last had it. I think it's the air that browns it, so the saran wrap helps block out the air and therefore from the quac turning brown as quickly.
I LOVE guac, but have only made it twice. I'm not a fan of cilantro (blasphemy I know). The batch I
really loved was just avocados, minced onions, and some garlic (I salted and crushed the garlic so it was easily spread/mixed). I thought that was just heaven.
