Aren't those soaked in urine to make them burn slower?
Actually the rope is soaked in potassium-nitrate (salt peter) in which urine is used in the process of making the salt peter. The salt peter doesn't make it burn slower, but hotter and more tenaciously. It can be made using 100% cotton clothesline rope that has been washed first. Washing removes the sizing (starch) and allows better absorbtion of the nitre solution.
The slow match catches fire best when the end is already charred. Once glowing, it's hard to put out.
I used to see similar slow match lighters sold as "WWI Trench Lighters"
Cheers,
Tom