Does anyone have an idea how to clean tannin stains from nice new concrete? We left a small pile of osb and dug fir sawdust on an exterior slab and a small amount of rain helped to leach out the tannins and produced a mild stain that the client would like to get rid of.
Will ultraviolet light or other such natural processes eventually fade the stain?
The only thing that would google up is “85g oxalic acid in 4½ litres of water” from a source with no direct experience with it. In case the slab is ever acid stained it seems to be a good idea to avoid acids and most other harsh cleaners. We’d hate to clean up the tannin stain only to pay for a new slab.
Cheers
Beer was created so carpenters wouldn’t rule the world.
Replies
white Vinagar or weak TSP solution..
rinse well...
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