Clearly marked? How about a total makeover?
I can just see some visiting kid catching his pants on fire, and his Mom grabbing the nearest fire extinguisher, not bothering to read the huge lettering marked all over it. She sprays the kid down thinking she has saved him, only to find out that it was fuel and she killed him. I can just see the look in the attorneys' eyes as they start calculating their share of the millions she will sue for!
I would look for something else to make a fire starter out of. If I had one, I would dispose of it, simply because when we get older, we get forgetful and markings we used may not last as long as the original paint. You know what is in it, it is clearly marked (or not clearly over time) and yet someone still mistakes it for an extinguisher in a panic. It is not going to work out well for anyone...
David from jax