Short version: when Cuba cut relations with the US, they wanted to get rid of Coke as an imperialist symbol, but they still needed the bottles, because they didn't have means of replacing them all at once. Coke was not that popular, though, but the Cuba libre (rum and Coke) was a slightly different problem. So they used the bottles for other things, and at the same time they came up with a Coke substitute (sold in other bottles, because the mixture was too close to the imperialist one). When they presented the substitute to Che Guevara, he said "it tastes like st" (or "like cockroach" on TV). E entually they improved the formula, and mixed with rum it was decent. But it wasn't actual Coke.

I Google-translated the article, and it seems to talk about the many Coke bottles in Cuba post-revolution being re-cycled to contain a local drink, the name of which I wasn't quite able to pick out of the translation, but which wasn't "Coke".