I am not a prewashers. If I suspect a bleeder I will soak a small piece in a cup of hot hot water to see..if it does out it goes! But now my question to prewashers. Some say as soon as they get home in the washer the fab goes......if you buy several different colors do you wash all together or separately? Do you go thru the whole wash, spin,rinse cycles? How much water, detergent. Then into a HOT dryer????? I must confess..when I do decide to make tablerunners I will soak the fab in a "dishpan" in the sink for a few minutes, then put on a clothes line in the laundry room to dry. I do this only because I do use a very thin poly batt and it does not shrink, so therefore all will be equal when washed.