I like to use minky backing for my quilts, especially for kids and grandkids. I don't usually prewash cotton fabric for the tops but I do wash and dry the quilts before gifting just to be sure nothing comes apart. I wash with warm water and use color catchers. Dry in dryer on medium setting. You should be fine washing yours when needed. Just to add, I do prewash flannels, tops and backs before sewing due to shrinkage. I have never had minky shrink or bleed.