Call Us

+1 (832) 302-3311

The Definitive Guide to Boat Cleaning with Muriatic and Oxalic Acid

The Definitive Guide to Boat Cleaning with Muriatic and Oxalic Acid

The Definitive Guide to Boat Cleaning with Muriatic and Oxalic Acid post thumbnail

Intuitively, cleaning anything with acid gives anyone second thoughts. Yes, acid is an effective cleaning agent in chosen situations but wouldn’t acid melt away your beloved boat? Cleaning tiles, aluminum, and other hard surfaces are safe with acid. Is cleaning your boat with acid safe, too?

Is It a Good Idea to Acid Wash a Boat?  

As your boat sits on the dock, algae, dirt, and grime build up on the hull and other exposed parts of your boat. These problematic spots are very tough to clean. Good thing there are these muriatic and oxalic acids to rely on.

These acids make the very difficult task of cleaning algae, rust, and grime off your boat into an easy task that anyone can do.

So, yes. Acid washing a boat is indeed a good idea, but be cautious, this procedure should not be done frequently. 

What Acids Are Used to Clean Boats?

Boat cleaning with muriatic acid or oxalic acid seems to be the chosen cleaning media for boats, yachts, and pontoons. Muriatic and oxalic acids are quite strong acids and can be corrosive. Therefore, safety for you and your boat is a priority in this discussion of cleaning boats with acid. If you know how and when to use these two acids, then you and your boat should be fine.

How to Clean a Boat with Oxalic Acid?

Clean a Boat

Cleaning boats is a very challenging job. Exposure to the elements when out on the open water leaves your boat with rust stains that only oxalic acid can take care of. Boat cleaning with oxalic acid could just be the technique you need.

Boat owners know that rust and rust stains are very stubborn and can not be easily removed with just any cleaning agent. Oxalic acid, however, can melt away and clean rust stains and spots without much scrubbing. Algae and other growth on your hull are the most stubborn to clean. Oxalic acid will be your best bet in regaining that shine your hull once had.

Wood surfaces and fixings age and lose their sheen with time. Fungi and grime also diminish wood’s appearance. You can use oxalic acid to revitalize and make the wood parts of your boat clean and ready to buff and shine again.

Whether you sail the high seas or the great lakes and rivers, oxalic acid is your best bet in staving off the rust and the damage it can do to your beloved watercraft.

Remove Rust with Oxalic Acid

Here are the steps you can follow to remove rust spots and stains on your boat, pontoon, or yacht:

  1. Clean your entire boat as usual.
  2. Have a 1:1 oxalic acid and water solution ready, and transfer this solution into a spray bottle or machine. Be sure to wear protective gloves, goggles, and a face mask when handling oxalic acid.
  3. Approach the individual rust spots and stains on your boat. Spray each rust stain and spot and leave the oxalic acid solution for 10 to 20 minutes.
  4. Do not scrub. The oxalic acid solution will work its magic, and you will see the rust spots and stains disappear.
  5. Rinse off the treated surfaces with lots of water.
  6. Wipe the treated areas dry and proceed to your usual boat exterior treatment and conditioning.
  7. Wax or gel coat the treated areas to further deter rust from forming.

Remove Algae from Your Hull with Oxalic Acid

  1. Have a 1:1 oxalic acid and hot water solution and put it in a metal spray machine or bottle. 
  2. Spray and soak the algae-affected areas of your boat.
  3. For a more effective treatment, cover the treated areas with a tarp.
  4. Leave the acid-water solution on the treated areas for around 20 minutes.
  5. Rinse off the oxalic acid with water and watch the algae get washed away.
  6. Dry off the treated areas and proceed to your usual boat shining routine.

Revitalizing Wood Fixtures on Your Boat with Oxalic Acid

  1. Use the same 1:1 oxalic acid solution. If you feel that the solution is too weak or too strong, adjust the acid-to-water ratio accordingly.
  2. Spray the oxalic acid solution on your deck and other wooden surfaces.
  3. Cover the surfaces with a tarp for around 10 minutes.
  4. Brush the treated wood with a scrub.
  5. Rinse the acid solution thoroughly with clean water.
  6. Dry the wooden surfaces thoroughly and proceed to your usual wood staining, varnishing, and buffing routines.

How to Clean a Boat with Muriatic Acid?

Muriatic acid is best for cleaning aluminum surfaces on your boat. The hull on your pontoon and other parts may be made of aluminum and will surely benefit from a muriatic acid solution treatment.

Here are the steps you can take to make muriatic acid work for you:

  1. Make a muriatic acid and water solution by diluting 4 parts water to 1 part of muriatic acid.
  2. Transfer this muriatic acid solution to a spray bottle.
  3. Scrub with a brush the surface you spray with the acid solution.
  4. Scrub until all visible stains and grime disappear.
  5. Rinse with clean water.
  6. Dry and proceed to your treating and polishing routine.

Important Safety Measures

Storing and using oxalic and muriatic acid is not a matter to be taken lightly. Follow these safety precautions whenever you store or handle these acids:


  1. Label the bottles with clear and readable labels.
  2. Keep your bottles tightly closed.
  3. Store in cool, dry places that animals and children cannot reach.


  1. Use safety gloves when handling muriatic or oxalic acid.
  2. Use safety goggles to protect your eyes.
  3. Use a high-grade face mask to minimize inhalation of dangerous acid fumes.
  4. Wash the acid residues of all boat surfaces with a pressure washer or hose.

Handling acid is a pretty dangerous proposition and may not be for anyone. If you feel that using acids for boat cleaning is quite intimidating, you can always use help from professional boat cleaners who can take care of acid cleaning techniques for you.