That's my problem with my current thermos - I need to keep the lid on so I don't spill it, but then it's undrinkable. I'll have to try the ice cube trick, but my worry is that my tea won't brew properly if it's too cool... well, first-world tea-drinking problems.
That's my problem with my current thermos - I need to keep the lid on so I don't spill it, but then it's…