Fuel for sale!

In these bottles is fuel for motos and cars. It comes in 3 different colours red ,green and gold(or red, green amber to stick with driving theme!) and is available for sale(very cheaply) just about everywhere. I don't know what the difference is between the different coloured fuels. I always used to put yellow in my moto. I cannot imagine the big drinks companies whose logos are still very clearly on the bottles would whole heartedly approve of their bottles being re used like this but maybe it is still a form of advertising for them.I remember being shocked about the potential danger of selling fuel in this way when I first arrived but now am completely used to it and have at times been mighty relieved to be able to get fuel so conveniently.