When something is said to be flammable, it means it can easily catch fire. On the other hand, when something is said to be highly flammable, the addition of the word 'highly' only shows how faster the item can catch fire. Highly inflammable materials have the chance of catching fire faster than flammable materials. Likewise, flammable substances cannot easily catch fire like the highly flammable substances. So, when some containers have flammable and highly flammable on them, it means the container can catch fire.
However, one has to be more careful with the highly flammable container than the flammable container. Some substances that fall under the flammable are ethanol, acetone, and gasoline. On the other hand, substances that are classified as highly flammable include dry leaves, cotton, firecrackers, books, and liquid flammables. In conclusion, highly flammable substances burn faster in a short time, whereas the flammable substances burn more slowly and for a longer time.