If the fabric looks clean, smells clean, that is good enough for me! I will continue to use my common sense. I can not prewash or scour everything. Just my HO! I don't like to prewash, harder to cut when you wash the sizing out, ravels, and I don't like the end results nearly as well. Afterall, I will wash it when completed. I run a pretty clean house as anyone who knows me will confirm, having said that, if we let everything we read dictate to us, gee we wouldn't have anytime to quilt or anything else. My friend is sending me an article on this type of thing. She said it makes you not want to bring any fabric into yr home. yikes, not sure I want to read it.
If we knew about how the food we eat was processed and what went into it, we would all probably be growing our own gardens and be a vegatarian only I guess.