I would go by what your store recommended and prewash the backing with white vinegar. Then wash the quilt once finished with color catchers. I finished a quilt this summer that had some black borders which should not have bled, but decided to use some color catchers (I used 3) and it still bled terribly and discolored the yellow in the quilt. I would much rather be safe than sorry. This is also a reminder to myself NOT to try and save a buck by buying Hancock's version of Kona.