I followed Srinath's advice in the FAQ and it worked great. Nice clean tank inside now makes for a happy GS :) That muratic acid is scary stuff though, made a lot of sizzle....
You think muratic acid is scary...you should take some time to play with ultra concentrated sulfuric acid. I use this in my organic chem. lab often and that stuff is thicker than 10w30 motor oil. Let's just say, I have fun burning stuff (like my latex gloves, doh!) while waiting for reactions to complete...