Second the vote for Starbrite Non Skid Deck Cleane
I would definitely second the vote for the Starbrite Non Skid Deck Cleaner. Without question, it is the best product I have found for tough dirt and stains (icluding spyder leave behinds). While I am not a West Marine basher, you definitely want to find this product at WalMart, as it generally runs about $6.00 a bottle there vs. almost $12 a bottle at West Marine. I have used the 3M wax several years, but am not impressed with the length of time it lasts. I just read the last issue of Practical Sailor and am going to try the Meguiar,s 50 One Step cleaner/wax in a couple of weeks.