What would you suggest I do with these 9 ounce tanks?

[Blitz]

http://youtube.com/watch?v=unkIVvjZc9Y it was this one acualy

Haha, that's funny as hell! I love it.

[Antonio]

Why not make something like this:

I assume the bottles have pin valves. You could use these like in the gun I made but then at higher pressures. > The barrel goes back and hits the pinvalve for a burst of air. Like this you could make a high powered multiple shot bb sniper:)
link

[Brian the brain]

If you can get hold of a pressure washer handle, you could use it for a 900 psi strafer.....