What is trading cloth?

A trading Cloth is Cloth that people traded,Like when Lewis and Clark were moving west the had to bring some sorta stuff to Trade with people for,food,poles,mostly needy stuff ,if you were smart you wouldnt trade a valualabule object with a non-needy object.Clark traded something with man he traded that object because the man had a dog,and he WANTED it because....Dogs are helpful because they can catch food in the sea if they can swim.Im just talking about lewis and clark but these are just examples.