I have always been able to find 12 ounce yellow Heet when/where I have needed fuel. I figure any container that can hold at least that is big enough for me for where I have toured so far. I have never had unopened Heet bottles leak so if necessary I could carry a second bottle.

That said, in a pinch, if I had to buy a larger container of fuel that I wanted to carry and didn''t like the container it came in I'd resort to whatever bottles I could find in the trash (pop, bottled water, etc.). If I was worried that they were a risk for someone drinking them I'd keep them packed out of sight and segregated from food and drink. That is an unlikely situation for me since I don't tend to need much fuel at a time.