Should you use Rust Cleanze or Oxy Cleanze to treat rust & remove rust stains?

Rust stains are one of the most common problems contractors come across on render, concrete, cladding, stone and metal surfaces. The challenge is that not all rust removers are suitable for all substrates.

At Benz Softwash, we generally recommend either Rust Cleanze or Oxy Cleanze, depending on the surface type and the result you are looking for.

Product overview

Rust Cleanze is a biodegradable, non-acid rust remover designed for porous and delicate substrates such as concrete, sandstone and limestone.

It is ideal where traditional acid-based rust removers could damage, bleach or mark the surface.

Oxy Cleanze is a thick gel cleaner designed for smooth or coated surfaces such as painted render, stainless steel, cladding and GRP.

Its sticky consistency allows longer dwell times on vertical surfaces.

When to use Rust Cleanze

Use Rust Cleanze on porous surfaces such as:

• Concrete
• Sandstone
• Limestone
• Brick
• Cement-based materials
• Other delicate substrates that may react badly to acids

Because Rust Cleanze is pH neutral, it is far safer on sensitive porous materials than aggressive acid-based rust removers.

It is especially effective for:

• Iron sulphate staining
• Fertiliser staining
• Rust from metal furniture
• Rust marks from BBQs and play equipment

Advantages of Rust Cleanze

• Biodegradable and non-acid
• Safer on porous stone and concrete
• Produces minimal whitening on concrete
• Ideal for delicate masonry surfaces
• Suitable for repeated applications if needed

Rust Cleanze is generally our preferred product for rust stains on concrete and natural stone.

Treating severe rust staining on concrete

Heavy iron sulphate staining can permanently penetrate concrete over time.

In severe cases:

• Multiple applications of Rust Cleanze may be required
• Residual staining may still remain after treatment
• A final brightening treatment may help even out the finish

For this, Oxy Cleanze can be diluted 1:1 with water and lightly applied to brighten the surface and reduce remaining discolouration.

Depending on the severity and age of the staining, treating the full area may be necessary for visual consistency.

Always test a small area first.

When to use Oxy Cleanze

Use Oxy Cleanze on smooth or coated surfaces such as:

• Painted render
• Coated industrial cladding
• Stainless steel
• Glass
• GRP and gelcoat
• Boat hull oxidation
• Painted metal
• Cast iron
• Smooth sealed surfaces

Oxy Cleanze is particularly effective on vertical surfaces because the gel consistency improves dwell time and reduces runoff.

Advantages of Oxy Cleanze

• Thick gel formula for vertical surfaces
• Excellent cling on paint and cladding
• Effective on stainless steel oxidation staining
• Suitable for GRP oxidation removal
• Useful for limescale and calcium staining
• Can brighten concrete when diluted correctly

Oxy Cleanze is generally the better choice when working on smooth or coated materials.

Quick tip

Porous surfaces previously exposed to iron sulphate can sometimes turn brown after treatment. This is usually caused by residual contamination deep within the substrate reacting during cleaning.

In most cases this can be improved with:

• A second Rust Cleanze treatment
• Or a diluted 1:1 Oxy Cleanze brightening treatment

Safety and responsible use

• Always carry out a small test patch first
• Keep surfaces wet during treatment where appropriate
• Do not allow products to dry on sensitive surfaces
• Rinse thoroughly after application
• Use appropriate PPE and follow product documentation

Further reading and support

For more practical softwash advice, visit the Benz Softwash Trade Tips blog.

You can also download our Product Documentation Pack, which includes application guides, SDS, PDS, RAMS, PPE and mask information, COSHH guidance and more.

If you are unsure which product is correct for your surface, the Benz team is always happy to help.