I, too, had a roll that was very creased, and quite unplayable.
I don't think it had ever been wet, but when I ironed it on a low
temperature setting and used the steam from the iron to make it
slightly damp, the result was very good indeed, and the roll came
back to its musical life.  I'm not sure if a frozen roll would be
an easy thing to iron, and being the mother of two children I've
done a lot of ironing.

A warning, though, it took me the best part of an evening as it was
a long roll.  The steam, of course, will stop the flames appearing!

Christine Robinson