The secret of the aluminum can: what is it hiding?

That's some impressive can polishing right there.

This video from MEL Chemistry shows how to reveal the secret polymer liner that lives inside every pop can (or Coke can if you're from Southern Indiana like your friendly neighborhood blogger is) using 'drain cleaner.' I assume it's something like Drano, a very concentrated solution of primarily sodium hydroxide. 

I do this experiment in class using hydrochloric acid in the 3M range, and it works just fine. Aluminum is, however, soluble in both acids and bases (not typical of most metals), so I have heard that sodium hydroxide solutions can produce the same result. 

I would certainly be careful with the 'drain cleaner', folks, because it's some nasty stuff. Weirdly, I'm more comfortable using 3M HCl because it's something I use with fair regularity at school. The Drano, however, gives me a bit of an uneasy feeling. Oddly, though, Steve Spangler's video of the same demo also uses sodium hydroxide as did most of the other videos I found showing this demonstration. That might be because buying hydrochloric acid can be a bit tougher (unless you know it's also called muriatic acid and is available at most hardware stores.)

Either way, be careful if you try this at home, but it's pretty frickin' awesome to see.