Boat was covered with tarp pretty tight. We did have a couple of nasty storms one of which did get some moisture in the interior that I did not realize until I uncovered it a many months later.
Problem : The upholstery was really covered in mold. I mixed up what I thought was a fairly weak solution of bleach and water in my deck sprayer and sprayed on on everything that had mold. I waited for around ten minutes than pressure washed everything it did come out really nice and clean.
The upholstery is red, black, gray and white.
Problem was in the white only !
The white has a light rust or brown color in it, not real bad but noticeable.
I may have made the bleach solution to strong and burned or etched the upholstery ?
The mold may have been on too long and bit into the upholstery ?
Not sure what the exact cause was but it is a problem.
I have tried many different products, soft scrub with bleach, Spray Nine, 409 cleaner, several different upholster cleaners no improvement what so ever.
Does anyone on her have any magic upholstery cleaner that they would recommend to me?
Thank You in advance for the reply !

Leave it open to sunlight for a few days . U will surprised what
The uv rays will do
Had it happen seen may mold stains disappear

try Magic eraser? had some watermelon stains that seemed nothing would remove, weekend in the sun... disappeared!

Open it up in sunlight as mentioned for a few days and get yourself some Spray Nine, works great .

Try sunlight first... If that don't work explore other options

Sun.

Magic eraser is abrasive and while it will work out some stains, use can damage the upholstery over the long run.

Many find the mold has worked in under the upholstery and discoloration will reappear.

I had the same type of splotchy stains on my Pantera. Nothing would make it go away completely.
I could get it almost gone with Clorrox Cleanup and the stain would come back from underneath after a few days..

worst case scenario, re dye the white parts. but try everything else first.

Go to a dollar store and buy a bathroom cleaner called "The Works". It's in a white bottle with a white and green label. Stuff works phenomenal. Also another trick is Westly's Bleach White for tires. That also works crazy good to removes stains. I used a combination of the two to clean my old sea ray vinyl seat that had the classic sea ray mold stains and it all came out like new.

Best I've used yet and its at the Home Depot.