How to Risk Life and Limb to Fill a Klein Bottle

A Klein bottle is one that has no separate inside and outside because they are both the same surface. It's not an imaginary shape, and you can buy a Klein bottle easily. Can you fill such a bottle with liquid? That's a problem, because gravity will work against you. But there is a way.  

James Orgill of The Action Lab (previously at Neatorama) tells us that it is air standing in the way of filling a Klein bottle. If we can remove the air, the liquid will fill the space despite gravity. He tests his method with aluminum cans, which is pretty cool, although I wouldn't recommend it unless you have proper safety equipment. On to the glass Klein bottle, in an experiment I wouldn't recommend even with safety equipment because all I could think of was what could possibly go wrong, and that's a lot. But as long as he's doing it instead of me, it's pretty cool. There's a skippable ad from 3:21 to 4:50.