Acid Burn/Vanadium stains on clay brick tiles
Hey would anyone be able to help me removing acid burn/vanadium stains (mainly greenish/yellowish with small amount of orange) from white/grey clay brick tiles? They came about (long strong) from Hydrochloric acid (muriatic acid) use on them to remove some insanely tough dirt. The darker red brick tiles now appear as if they are consistently wet (darker) as well.
I've looked on the internet and tried what was recommended in Bleach/Caustic Soda (Sodium hydroxide)/Rust remover and it has had no effect. I don't have a high pressure cleaner but would that do anything?