Patriotic material is still stiff after washing before and after making quilt. Any suggestions on how to get it to soften?

Have you tried white vinegar in the rinse?

does the fabric have painted designs on it? like some white on whites

does the fabric have painted designs on it? like some white on whites

extra rinse and hang out while windy??

wash it a few times and dry it in between. sometimes it takes a few washings to get fabric soft as can be.

why is it stiff?
some fabrics remain stiff forever- nature of the beast-
regular quilting cottons should soften with every wash- they just get better and better-
if it is a painted fabric or has some sort of coating on it- prehaps try vinegar in the wash- try liquid fabric softener-as apposed to dryer sheets- which are good for static cling- but not so much for softening-