Baking Soda and Vinegar: Are there any secondary reactions? I want to run a Lego Pneumatic Engine on the CO2 that is produced, but before I do, I want to be sure that that's the ONLY gaseous product from a real-world reaction.  Everyone seems to assume that it is, just by omission, but no one actually says it.

I'm sure it would run, but I'd rather not damage the ABS plastic or probably-steel parts (shiny metal piston shaft), or a rubber seal or the factory lubricant or something else that I can't see.  CO2 seems inert enough by itself, but is that really ALL I'll get?
(assuming of course, that I keep the foam out)
It seems to me, according to the comments on the question, that there are NO additional reactions or products to worry about.

However, because of the foam, some of the original reactants can be tossed up, and find their way into the later parts of the apparatus as a haze/fog/cloud that is not completely inert.

Is that more-or-less accurate?  I'm trying to get an answer here, and not just a string of comments.