So i was watching the food network the other day and say this show on fried food. There was a place in New Orleans that was famous for fried chicken (willie mae's scotch house). But there was a place in Memphis Tennessee called Dyers. Apparently they fry their food in almost 100 year old grease. here is a link to their place. Dyer's Burgers :: World Famous Beale St Memphis Tennessee :: Official Website
Hmmmm. If you have 10 gallons of grease and you strain it every day and top it off with a gallon of new grease to cover evaporation loss, loss becoming part of food, and lost in the strainer with the crumbs . . . then you have, at best, 10-day-old grease, not 100-year-old grease.
I went to Dyers about 12 years ago. It was a good burger. I have had better. Still, if you are in the Beal street area give it a try. Around Memphis they make a big deal out of the 100 year old grease. I think it is just great marketing.