Edit: whoops, I missed the “il” part in “not illegal”. Anyway you should definitely not do the following. Allegedly doing the following would be arson, and society frowns upon such things.

Easy:

1. Identify company
2. Wait until it’s a weekend night. We’re not after the wage slaves after all.
3. Mix polystyrene and gasoline. Remember that gasoline can melt some plastics, so if using a plastic container for mixing do a test first. You do not want napalm all over the place.
4. Fill the gooey substance in glass bottles.
5. Cap the bottles. (see #7)
6. Drive to the company.
7. Open bottles and put wicks in them. (important not to do this earlier. Driving with open gasoline containers in your car will make you drowsy and is a fire hazard)
8. If you haven’t already got gloves on, put them on and wipe down the bottles - you may have to leave some at some point.
9. Have accomplices trigger fire alarms all over the local fire department’s district. Either automatic fire alarms will be discarded for a bit or the marshall will be tied up investigating.
10. Light a wick, throw the bottle at the company, try to get it to break a window.
11. If you’re out of bottles or you see blue lights cheese it. Otherwise go back a step and repeat it.