What's the best thing to use to remove those green water/mould stains from concrete?
Hi @Prof,
I trust Workshop members will have some great suggestions for you.
In the meantime you might like to check out these previous discussions for ideas:
Good luck,
Jason
What have you tried so far @Prof? Sometimes just a pressure washer is enough. But if you don't have one, I'd start off with something fairly safe like diluted nappy san or amonia with a stiff broom and see how you go. If that's not working, then you could step up to liquid chlorine or pool acid. (Just use caution and protective gear.)
Let us know how you go as its a common problem, although typically it would be people complaining of oil stains, which you wouldn't want to use chlorine for as it might react.
No worries @Prof. Let us know how you go. You might want to look at investing in a pressure washer if its a job you need to do often and/or you have other uses for one. They are very handy and use a surprisingly small amount of water.
I looked at a pressure washer some time ago, but I never followed it up as other expenses got in the way..
When the driveway has dried, I'll try the bleach first and see how it goes..
I'll let you know when I've done it..
Hi @Prof, I use and have been using Oxalic Acid for years to semove stains from concrete and timber. it is sold at some paint stores for use as a wood bleach. It is often sold in small bags. To use oxalic acid, mix one-half cup of the powder in four litres of warm water and mop it on the stain. Let it work for five to 10 minutes, keeping the stain wet, then scrub with a stiff-bristled brush and rinse. You can also get it from bunnings 2kg for $30. I prefer the crystal form as aginst the liquid form as I can then mix it as strong as I like. https://www.bunnings.com.au/diggers-2kg-rust-stain-cleaner_p0960276
Just wondering if you have made any progress removing those stains?
Hope all is well.
Hi Jason..
I haven't removed the staining yet..My gardner is coming in a couple of weeks time and he says he might be able to remove them with a high pressure water cleaner..
I'll let all know if he's succesful..
Thanks for the update @Prof. I hope you have some luck with the pressure cleaner.
If memory serves me well, CLR or CLR OIL & STAIN remover will do the job well, just spray a tiny corner of the stain if you like to test it. But for my workshop it removed old oil stains etc excellantly. Both Available from bunnings.
personally, Im not a fan of high pressure water blasting concrete floors as it tends to damage the fine top surface over time.
Thanks for your input Johnny..The concrete in this case is a carport floor..It's already pretty rough and cracked!It won't cost me anything if the gardener can get it off with a pressure cleaner, so worth a try at least..
If it doesn't work I'll have a couple of alternatives to try..
Fantastic. Many thanks for the update @Prof. Glad to see you got a great result.
well here is one way that you will all say no way but trust me my father was a Grano layer and he knew his stuff
he passed away in 2011 but that's where all this advice stopped
many many years ago when I was 17 (around 1980) I asked him how can we get the car oil stains out of the driveway (he put in) as my car leaked oil a few times.... well he said don't worry go buy a 2litre of coke cola and take sip, so you know its the real stuff and give it to me and i'll do my magic he told me
so he did, he pored it over the patch of oil waited 20mins, scrubbed it with a hard brush, not metal type one and hosed it off and all was cleaned......
if I had photos I would have shown you but back then it wasn't on my mine and to this day I have used the same method all the time
so you can say what you like but it works for me and its the cheapest option as coke is wasted when some don't drink it all and that's why I never saw oil on our drive ways oh and we NEVER left a bottle laying around or dad would steal it for cleaning....
have a nice day all
Thanks for joining the discussion @icemanx and sharing your experiences. Looking forward to seeing more of your posts soon. Feel free to post whenever you have something to share or need a hand with a project of your own.
Welcome,
Ah.The wonders of Coke..The miracle liquid..The be all and end all of liquid cleaners!!! 😌I used to clean penny's with it when I was a boy! 😀..but I never heard it could clean oil off concrete!!.I wish I had known that many years ago when I was messing around with cars..Thanks for the tip icemanx..
well not my tip it was my Fathers and he was the Grano worker/creator that knew how to work with concrete
so yes he knew his stuff....
Easiest option. Degreaser just scrub it with a hard broom and hose off.
Welcome to the Bunnings Workshop community @SmokeHound. It's fantastic to have you join us and many thanks for jumping into the conversation.
That's a very helpful tip, I'll have to try the degreaser on my own driveway.
We look forward to hearing about the projects you have going on around your house and garden and would encourage you to let us know if you ever need assistance or have something to share with the community. I trust you'll find loads of inspiration on the site as our creative members are contributing their own projects here all the time.
Mitchell
