Sometimes you need tender that will catch fast. Perhaps you are using a firesteel or your lighter has died and it can only make a spark. Maybe it is very windy and your match will only stay lit for a second. There are a lot of times when you simply do not have the luxury of starting a fire with an open flame. Times like this call for cotton balls!
Cotton balls make a great tinder by themselves. However, we can improve their performance with some petroleum jelly.
This is messy. Take a cotton ball and completely coat it in petroleum jelly. It will now catch fire very quickly. How quickly? Watch this video:
It will take a spark from a firesteel or flint faster than almost anything. Their burn time is about 5 minutes, which is plenty of time to light damp kindling.
They are not without drawbacks however. First of all, they are very messy. You will need a container dedicated to them. You cannot simply throw some in your pocket. Secondly, they are only minimally waterproof. If they get damp they will burn, but become much harder to light. How hard? I have a video for that too!
They will not light if they are soaked.
Cotton balls have their place in a fire making kit. In fact, they are my first choice. However, if you don't carry a secondary method of starting a fire you may be in trouble.