Thread: Removing oil stains from concrete??

I used pool chlorine....just the powder stuff. Make the stain damp (NOT wet!) sprinkle it on, wash off the next day.....if anything, the stain is white instead of grey lol
Sea salt (or butchers salt)also does a fair job and is not toxic to the pets, just use it the same way but leave in place for longer...maybe 3 days.

When the sewer line under the carport blocked the concrete was cleaned very well when the washing machine waste water split over - Omo. Try same with warm water for better penetration. Any petroleum based solvent will move the stain deeper/wider which may make it less obvious.

Originally Posted by Rovernaut

we used to use hydrocloric acid and caustic mixed together in hot water to clean concrete stains

Why not use a strong salt (NaCl) solution in the first place? You are just making it on the spot!

[HCl + Na(OH)2 = NaCl + H2O]

Cheers,

Lionel