i have taken pillow cases twice now and they are great!!!
Just put everything in a zip lock baggie with waterproof pens and pillow cases and out a card with your name and room number on it too.
Take this to guest services the FIRST day and ask to have them autographed. They will fill out another card with your name at the desk, but still include yor own in case it gets lost.
I think colored markers look best, but dont use light pink or yellow as they dont show up as good as red, blue, green, purple etc....
Wash and iron anything you use so the color sets in better.
Lots of people do this, so to make sure they have time enough to do this, pleae make sure you take it the FIRST day to guest services so they have the entire cruise to do it.
They will return it to your oom the last evening of your cruise.
It is free,