I pre-wash all my "yardage" fabrics including fat quarters because the sizing they put on fabrics irritates my skin, and sometimes my eyes. It's nice to know if the fabric will run or fade too, but mostly I need to be able to handle them!
I use whatever "free & clear" detergent we have at home at the time, sometimes with ammonia, sometimes with washing soda. No Evil Softener or dryer sheets. (If you want to see me claw my skin off, give me a towel that was washed in Tide and dried with dryer sheet.)