Part I of this project is here. Once outside, light up one of the pieces.
As you can see, it burns quite good. Elapsed time since lit: Less then 1 minute.
Elapsed time: 2 minutes
Elapsed time: 3 minutes. The flame is now about 3 inches higher still above the photo.
At this point, I put the fire out with just under a coffee cup of water then drained it off.
I was able to relight the fire with one wooden match....YMMV.
Each piece of egg carton will burn anywhere from 5 to about 10 minutes depending on what you put in each egg compartment for tinder and how much. These are light enough that I keep 4-5 pieces in my backpack at all times and come in real handy when trying to start a stubborn fire in foul weather conditions.