On 02/08/2018 22:08, Peter Parry wrote:
On 2 Aug 2018 18:11:48 GMT, David wrote:


In the kitchen there is a nice wood worktop which has turned black around
the sink. Yes, it was a rental property. Looks like a wood block work
surface and far to good for a rental. Light colour.

Anyway, once the wood has been soaked long term and turned black is there
much that can be done to revive it?

Yes - Oxalic Acid . Wash several times with a solution of Oxalic Acid
will remove the black and restore the colour.

I think that might work. My guess would be iron tannin complexes formed
in the wood have turned it black. Or nasty black/drak green bacteria
algae - either way oxalic acid ought to be aggressive enough to zap it
without doing too much damage to the wood.

Peroxide would be another option to try as a bleach if the stains are
very stubborn but it might denature the wood.

--
Regards,
Martin Brown