Originally Posted by Naturalmama
Hmmmm.... most of the squares are already cut, but I do have a piece or two that I will be cutting myself - plus I need to cut all of the sashing which will be black, so maybe I should prewash..... maybe I can do it in a bucket instead of the machine...
I definitely would not wash do any prewashing of the already-cut 5-inch squares. I personally also would not mix prewashed squares with unwashed squares, so I would just cut the remaining fabric.
I would test the black fabric for dye stability before using it. Drop a piece in a clear glass of water and see if it discolors the water (give it an hour). Also, rub a piece of white fabric across the dampened black fabric to see if any black transfers to the white. Most black cotton fabrics have been colorfast for me, but I know that blacks can be bad about transferring color. You definitely don't want black bleeding!