@Dolores71 I read an article that stated that hotel chains and bnb's started to put sticky notes (see images) to assure customers of cleanliness. (Search for "Your hotel duvet cover has been laundered" for full article.) Some hotels are believed to only wash duvet covers, counterpanes, blankets, pillow and mattress protectors etc. once a month, even yearly. Apparently customers were assured and pleased to see these notes. I personally wouldn't do it, but each to his own.
@Kathie21 I do the same – leave the folding creases. I have had people get on a chair and run their fingers over the top of the wardrobe, they mentioned it to me and said how clean it was and that in some hotels they had found dust on high picture rails and tall wardrobes! The mind boggles at such people.
I think the best compliment I had was for my battered old floors, some people mistake battered for dirty, the guest wrote 'scrubbed clean'. She lived in an old farm house so could spot the difference between battered/distressed and dirt. I may add her words to my description.