I'm one of those that would never use dryer sheets because of the inherent perfumes, chemicals, etc. doesn't matter if they've been used, I'm not comfortable handing that issue off to anyone in a finished quilt. Not with the allergies and sensitivities, asthma etc. that are common today. You can get fairly inexpensive muslin anywhere. It doesn't have to be high grade because it's being used as a foundation base.