I use white cotton thread (mercerized) for my furled leaders construction. Just like your blue jeans these furled leaders last forever and a day...
You can also used colored cotton thread (mecerized) with each of the two runs a different color or shade of color, depending on the stream/river coloration...
~Parnelli
I spent 4 years perfecting my "Big Furled Leader Formula", that have have sent out at no cost to the party requesting the CD, to flyanglers all around the world...
"Everyone you meet in life, give you happiness! Some by their arrival, others by their departure!" ~Parnelli