I don't use a dryer sheet when I prewash but I do use a wash cloth that I wet, wring and dampen a little with white distilled vinegar. No residue from dryer sheets but softens a little. I wash flannel couple times in hot water then throw into a hot dryer. When I use dryer sheets I use Seventh Generation. Perfume and dye free. One half sheet will do 3 large loads.