Just got back from Kauai and was charged an extra $75 dollar cleaning fee. Like many of the other posters who have had similar experiences, the fee was for a really small amount sand. It appears that this is pretty common with Avis in Kauai, specifically. They played it off that they were cutting me a deal by not charging me $150. If your renting from Avis you might want to make sure that their rate is atleast $75 cheaper for the week than anyone else just to hedge your bets.