For general deck cleaning, unless there is a specific stain, always start with a relatively mild, biodegradeable surfactant. Not strong enough to remove wax or corrode metal, but enough to loosen what the birds left, hard water spots, and atmospheric dirt. One possible remedy is a little spot cleaning with biodegradable laundry detergent. Today, most detergents are biodegradable.
The EPA has banned the most damaging ingredients in laundry soap, and the EPA Safer Choice program sets minimum standards for degradable products. Wet the boat with water to help soften the thick dirt, mix about -cup of laundry soap per three gallons warm water, scrub, and rinse. Yes, it is biodegradable (it is required to be), and a lot cheaper than many boat soaps. You will have it on the boat for laundry, too. It is also good for upholstery and carpets, although it is good to follow those applications with a rinse in an anti-mildew solution.
Metal stains. Use acid cleaner for rust spots, black streaks, and other metal stains. You probably already have a de-scaling chemical for your boats head hoses, engine cooling passages: Rydlyme, CLR, or vinegar. A year ago I was trying to remove a pesky yellow stain on the topsides. Saving a trip to the store, I diluted the CLR with water at a ratio of 20:1, sprayed the sides down, wiped lightly to even it up, and waited 15 minutes before rinsing. It came out as white as new.
Mildew. Clean first with either alkaline cleaner or vinegar, followed by diluted bleach or Formula B (no rinse with Formula B). The real secret is prevention through eliminating dampness.
Soft Vinyl. Clear vinyl has requires special care-review Practical Sailor articles on clear vinyl care. Dish washing liquid is a safe choice, as are specialty products from Imar, Star brite, and Plexus. Vinegar for tough water spots. There are many cleaners that can do real damage to soft vinyl windows, so this is one area where you shouldnt experiment. Weve done the dirty work.
Decks, Black Streaks, and Bilges. Many general purpose cleaners overlap here. Acid cleaners are best for corrosion product streaks, degreasers are great in the bilge, and general purpose cleaners loosen general grime that has found its way into the pores.
Upholstery, Canvas and Ropes. These are all fabrics, so laundry detergent works, as do general purpose cleaners and deck cleaners. The key is to soak first, remove all of the soap before drying (remaining laundry detergent is great mildew food-either rinse a lot or extract with a wet vac), and to finish with an anti-mildew agent in the rinse water (either our DIY Formula B or a BAC-based pool algae control agent). Mineral spirits can also be very effective, though the covers should be removed and the cleaning done outside.