A windy day would be lovely, but I live in the desert so they just bake to a crisp in the sun.
I do wash them at 60.
Will try ironing.
Will try white vinegar.
Will avoid softener because it's horrid gloopy stuff that serves no purpose and makes us all a bit itchy.
I like warm fluffy tumble dried towels. Lovely and absorbant and they don't take a layer of skin off my shins.