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

A sugar cube also works in place of the mento and I'm fairly sure they are cheaper.

It would be interesting to try a bit of sandstone or something like that.

Soda water from a soda stream should work pretty much as well as cola.