RMR Marine Hull Cleaner, Heavy Duty Boat Wash for Cleaning Slimy & Grimy Surfaces, Rust, Stain, & Water Spot Remover, 24 Ounce Spray

Just spray it on and wash it off. I did not need to apply it with a rag. Cleaned the yellow off from the bottom of my hull nicely.

This product does what it says-removes stubborn stains and rust-but is incredibly strong in smell and harsh on your body. The smell reminded me of the time I mistakenly mixed chemicals to clean a toilet, which I found out was dangerous! You need to do this in a well ventilated area (not a warehouse) and wear gloves and maybe mask and goggles. While this works well, I question how often I would need to use this or would want to because of how strong it is. I would probably opt for another alternative if I had the choice. If you are willing to take precautions and or suffer the smell (inhaling and aggravating your skin), go ahead. It is heavy duty.

I bought a used boat about a month ago. There are areas on the boat with a stain that regular car/boat soap won't get rid of. I used this cleaner on some of those spots and it did remove some of them.I'm not familiar with the RMR brand but they make a variety of household cleaners and now marine specific cleaners. What I like about these cleaners is that they're made in the USA and they're environmentally friendly. They're safe to use on my boat's gelcoat.Overall, this was a pretty effective cleaner for some of my gelcoat stains. I recommend this cleaner.My rating method:1 star - terrible. I wouldn't consider buying it.2 stars - marginal at best. Doesn't meet the minimum requirements or quality to be useful. Buy it at your own risk.3 stars - average. Meets the quality and requirements for a product of this type but is nothing out of the ordinary. If the price is good, I'd probably buy it.4 stars - better than average. Exceeds the typical quality of a product of this type and has a few extra features not usually found on other products of this type. I'd buy it.5 stars - exceptional - far exceeds the quality of products of this type. Hard to beat the quality and features included. Best value for the money. I wouldn't hesitate to buy it.

Ten stars if I could. This stuff managed to get rid of stains that have been haunting me for close to a year.Be forewarned, the smell is caustic. As in, it feels like you are standing a few inches from a fire because your eyes and lungs will go into panic mode when you spray this stuff.As long as you’re standing downwind, and no one else is around, it’s easy to spray and run away while this does its job. Three minutes or less is all it took to completely remove stains on the back deck of our boat. I know some stains were rust stains, and the other stain was a footprint (?) but I couldn’t tell you what was stepped in to create it.Before using this, to get rid of the footprint I tried everything using a hand held scrub brush and elbow grease (soap, baking soda, bleach, soft scrub, etc). Then I tried it all again this time using a magic eraser, which 99% of the time always magically erased- but the footprint and rust were part of the 1% club.I just sprayed the stains, ran away so I could breathe, and literally watched the stains fade from afar. About two minutes later I gave the stains a scrub with a rubber bristle brush and they completely disappeared.Afterward, I sprayed off the deck and I got a LOT of suds. A LOT. It’s possible that there was some soap residue left on the deck but honestly I think this product was the culprit.The boat deck is fiberglass with gel coat on top.Anyway I’m very happy with this product and definitely recommend it!

This seemed like a simple enough product, so I gave it a try for my glass windows. The windows have a lot of mineral deposits from the sprinklers overspraying the area. I read all of the instructions (VERY small print), and it sounds like you need to be super careful not to get this on your skin, breath the vapors, etc. I wore gloves, a mask, goggles, a long-sleeve shirt, and a hat so I would be sure to be safe. The instructions did say to leave it on for 2 – 3 minutes, BUT, not to let it dry on the area. After about a minute, I could see that the edges were just about ready to dry, so I scrubbed a little and then rinsed it off, then buffed the area. Unfortunately, the mineral deposit haze was still on the glass. Maybe on a cooler day I could have left it on the windows longer, so someone else might have better luck with this product. It might work better on different surfaces, but it didn’t work for me on the glass. Considering all the precautions, which included not getting it on the metal frame, it’s too much work for me.

This hull cleaner works well, it is a thicker consistency so it sticks to the hull and penetrates deep stains and makes removal super easy!

I used this stuff on everything that had stains and water deposits. I did let it sit the recommended few minutes and on really this scale I used a scraper, but it came right off! I did accidentally leave it on aluminum and it tarnished it, but had I not done that it wouldn’t have damaged it. I do recommend wearing gloves. I love this product!

I followed the directions perfectly to use this to remove some light rust stains and some alge lines on my waterline. It works (maybe), but only if you scrub. It will not do anything just letting it sit and hosing off - as instructed. In fact, I'm not entirely sure this does anything at all. Simply scrubbing without using the product (only using water and a microfiber cloth) had a nearly identical effect.