Hello!
I am a rookie, but the first thing I do is wash everything.
My last job gave me a bad headache, because I bought a kit of fabrics do come from 2.50 square inches and were not washed. Upon completion of the project (a watercolor of 323 squares) and before the border, I had to wash it had "touched" a lot (for my lack of knowledge) and the darker fabrics lost their colors! I lost a job almost 3 weeks! You can "save" with a "trick" but it was a terrible experience!
I put the cloth in a transparent bucket with water, leave 15 minutes, rinse and hang up.
I love batik, I lose the reds, burgundy and blue .... and so far almost all have faded! We do not sell these special towels that I see on the web.
First was soaking in vinegar, but did not work.
Now I use warm water + salt and is working well even in the batik!
My bad experience leads me to wash almost everything!
Good luck to you!
A hug!