Now to convince Security that the red bottle covered with warning messages is harmless!
like Caerau said, it mixes with water very easily.
Wash out the bottle with hot water, including flushing water through the valve/tap.
It will be just the same as a rinsed out whisky bottle - if you can't smell anything, it's OK
You could even put wine in, and tell them it's not a fuel bottle at all, but that you've been using it with those supermarket fill your own bottle taps you see sometimes, so you don't have to drink the lot at once.