Re: Jib sheets stiff
You can try simply towing them behind the boat for a while (no prop!) to get any kinks out and let them straighten. But after that-
Front-loading washing machine, just a little soap (not detergent) or plain warm water. Put the sheets in lingerie bags (there are some stronger similar bags sold under the "Tide" brand now as well) or pillow cases. Then air-dry, laid out in long runs if you can.
Getting out the salt crystals also prolongs the life of the line, as they act like fine sand and cut it apart from the inside out.
I haven't tried fabric softener but it shouldn't hurt, it is usually some type of water-soluble wax.