Recently I read the Freakonomics book. Do read it, unless you already haven’t - it’s very entertaining and thought-provoking.

Then, in a similar vein, I ran into this BBC article, which states: “Analysis of notes from a selection of Spain’s major cities showed that each one carried an average of 25.18 micrograms of cocaine.”

In other words, people snort so much of the illicit substance through rolled-up notes that the notes in circulation will have measurable amounts of cocaine in them. It’s unbelievable, but true.

Since people dig huge holes to the ground to get out minerals worth less, would this resource be somehow commercially exploitable?

Let’s do the math!

Assume you are in control of a shop selling relatively inexpensive goods at some busy area. Let’s assume, on average, there are 100 customers daily, each of who bring (on average) 2 notes to the shop. This means 100*2*25.18 micrograms = 0.005 grams of cocaine per day. The shop is run year-round, so let’s say about 330 days per year - this gives about 1.67 grams of cocaine per year per shop.

If you are a big franchise - similar to Subway, McDonald’s, Pizza Hut, whatever, and you’ll have, say, 1000 of specially equipped shops to “farm” or perhaps rather “wash” the cocaine out of the notes, you would be able to pull in a hefty 1.6 kg of cocaine every year, perhaps just in time for the company Christmas party.

Anyway, 1.6 kg may seem like a lot and I agree, it does. But you can fudge the numbers as you see fit, and see what the result is for you. Here’s the formula - similar to Drake Equation, but doesn’t involve little green men:

X * N * C * d * S

X = customers per day, on average
N = notes brought in by customers per day, on average
C = amount of cocaine in each note, on average, in grams
d = days in a year the shop operates
S = number of shops

In the example above, we’d get 100 * 2 * 0.00002518 * 330 * 1000 = 1662 (grams).