What is the etiquette with tanning at a salon?

I recently decided to get myself a bit of a tan not only to add some color, but because I want to go to a beach not too far from now, and don’t want to be the whitest guy on the beach. What is the etiquette for tanning in these booths? are you suppose to be in the nude? Is tanning in the nude against the rules? Does someone clean the tanning bed after I leave before anyone else gets in it, and vice versa? I tanned just the other day, and kept my underwear on, but just rolled the pant legs up a bit, and rolled the waist line down a bit. Does anyone know of any unwritten codes that everyone follows in this type of place?