How to clean lead flashing with Benz Oxy Cleanze oxidation removal gel?

October 24, 2017

Benz Softwash Bio Cleanze DDAC biocide & Benz Softwash Lightning Cleanze SH sodium hypochlorite biocide

After softwashing a surface such as a roof, which has a lot of lead flashing, with a sodium hypochlorite product (eg Benz Lightning Cleanze) the sodium hypochlorite may react with the lead and discolour it.

At 5:1 Benz LIghtning Cleanze may bring about oxidation on lead flashing, as will any sodium hypochlorite based product. At 10:1 it is classified as non-corrosive and is unlikely to affect lead, except – possibly – if applied on a very hot day.

We recommend rinsing the lead immediately prior to applying Lightning Cleanze, keeping the product away from lead as much as possible by skillful spray technique, and rinsing again immediately after application.

Rinsing prior to softwashing with any sodium hypochlorite product, rinsing during softwashing, and then a final rinse when the softwash treatment is complete, will go a long way to protect the lead.

Quick tips:

  • When wetting the lead, there is a possibility of diluting the Lightning Cleanze that has just been applied. If this happens just give the surface an extra application by spray or brush.

  • Another way of working is to treat the render below the flashing first, and give Lightning Cleanze some time to activate before wetting the lead.

Of course sometimes rinsing alone just isn't enough.

That's where Benz Oxy Cleanze oxidation removal gel comes in ...

Using Benz Oxy Cleanze oxidation (eg following treatment with sodium hypochlorite) remover to clean lead

New lead has a whitish/blueish appearance that "dulls down" to the grey colour we are familiar with, eg. the lead flashing on roofs.

Oxy Cleanze will quickly remove oxidation stains on lead flashing caused by natural oxidation and softwashing with sodium hypochlorite.

Quick tip: Modern lead may not be pure and so can discolour over time. Benz Oxy Cleanze will not reverse this form of reaction.


A controlled test using Oxy Cleanze oxidation removal gel to clean lead

We coated the lead in the photo below with neat Lightning Cleanze and left it for 60 minutes. Then we rinsed and dried it. The temperature was 6 ℃.

Lead treated with Benz Blackwash sodium hypochlorite mix

In the photo below we applied Oxy Cleanze rust remover by brush and left it to work.

OxyCleanze oxidation remover applied to lead treated with sodium hypochlorite

The photo below shows the results after only 30 minutes.

Result of treating lead oxidation with OxyCleanze oxidation remover gel

Two hours later we rinsed the Oxy Cleanze gel from the lead.

Oxidation removed after rinsing OxyCleanze from treated lead

The results we achieved would be satisfactory for most lead restoration work, e.g. after lead has been cleaned with a sodium hypochlorite based product.

Apply a second coat if needed. In the photo below the far right section was treated a second time. We left this overnight (it was winter and cold – we do not recommended leaving a treated surface overnight during the warmer summer months) and rinsed the oxidation removal gel from the lead.

Benz OxyCleanze oxidation remover applied twice

The photo below shows what it looked like when dry. Notice that the lead looks brighter and more blue/white than the dull grey we are used to seeing on lead flashing. It will gradually "dull down" with age (btw: the change of background colour was due to poor lighting conditions).

Oxidation cleaned from lead by Benz OxyCleanze oxidation remover

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Using Benz Oxy Cleanze to clean heavily oxidised lead flashing

On the property below, one application of Oxy Cleanze was enough to remove the yellow staining caused by softwashing with sodium hypochlorite, along with some ingrained oxidation.

Yellow staining on lead by sodium hypochlorite and oxidation

After four hours at 5 ℃ we thoroughly rinsed Oxy Cleanze rust removal gel off the lead flashing with water using a garden hose and some light brushing. The photo below shows the result:

Benz OxyCleanze removes oxidation from lead roof flashing

Quick tip: The ingrained oxidation, which had built up over many years, cannot be removed without the repeated use of Oxy Cleanze rust remover, which could cause whitening of the lead .

This may be undesirable in some situations and for some customers. So always inform your customer of the possible results of repeated applications of Oxy Cleanze and allow your customer to make the decision as to whether to go ahead.

Rmove oxidation from lead flashing

Natural weathering will reverse the whitening you can see in the above photo as the lead flashing tarnishes and dulls down.


  • Although multiple applications of Oxy Cleanze may turn lead white, this is normally not a problem when reversing the effects of softwashing with sodium hypochlorite.
  • Oxy Cleanze is less effective on very old oxidation stains.
  • For the best possible job, after treatment with Oxy Cleanze wipe the lead with patination oil.


We hope this information is helpful.


Ben, Leo & Fiona


Click Here to explore the full range of Benz popular softwash cleaning products

Benz Softwash Bio Cleanze DDAC biocide & Benz Softwash Lightning Cleanze SH sodium hypochlorite biocide

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