Mkotch

I don't wash anymore unless the fabric is bright pink or red or batik. I test a small section to see if it might run. I don't usually wash backings because, unless I spray starch heavily, they tend to pucker more when washed. Remember also that your batting will shrink a bit when washed. I often wash the whole quilt when finished and like the look afterwards.

sewvicki

I wash my 108" backing and try to take it out of the dryer the minute it stops. I folded it in thirds to iron it. Not an easy task, but worth it in the long run. If the other fabrics in the quilt have been washed and the backing has not, it may distort the whole thing. Not my favorite part of making a quilt, but IMHO, a necessary part.