Spoonimo

Greetings everyone! I have a seemingly simple question that has been bugging me for a few days. Obviously, the Diet Coke and Mentos reaction has become quite popular on YouTube, as well as in classrooms. Usually the demonstration accompanies a discussion about the nucleation points on the Mentos that cause the CO2 in the soda to be rapidly released. In order for teachers to save money when repeatedly doing this demo, would it be possible to create artificial Mentos? By this I mean make an object (not sure if any shape would work) that had the same microscopic cavities as the candies, but was made out of a material that didn't wear down when exposed to moisture (making it reusable for future experiments). Additionally, might there be a way to produce a substitute for cola? Perhaps by using a SodaStream machine, or the like. I realize this isn't the most ground-breaking idea ever, but I thought I'd get some more opinions on it's plausibility. Best Regards, Spoonimo