OK, so maybe this isn't really their recipe, as they always seem to deny it's "out there" and that it includes apple juice. But rumor has it that friends of mine knew someone that dumpster dove to find out what bottles they threw out the most, then brought some margs home with them and "reverse engineered" it. Who knows, but it tastes pretty good anyway.
On December 18, 2015, I received the following email:
"Hi there. My name is Bruce. I was doing a search for Duffy's Lime and stumbled upon your site with the Duffy's reference. I am the actual "guy who broke the code", so to speak, along with my wonderful student, Mark, who did most of the dumpster diving while I neatly lined up the different bottles of ingredients, on the ground beside it. We simply counted them all up and extrapolated the ratios/proportions and Voila! We had some tweaking to do, of course, but that was part of the fun in getting it perfect and us getting sloshed on true Rio Margs in the mean-time. That was back in the early '90's. Thought you might find this interesting and fun. By the way your posted recipe is, amazingly accurate, except that we would often like to argue about there being another shot or two of Cuervo in it."
3 parts Jose Cuervo Gold Tequila
1 part Juarez Triple Sec
3 parts Beiche's Lime juice (this is now called Duffy's) - or Rose's Lime Juice
1 part Water (we think this must have been ice)
2 parts Apple juice
Mix, drink and enjoy!