oxalic acid

[SAWDOC]

How long will a mixed/diluted cup of oxalic acid retain its chemical property to bleach wood stains?

 

[VicS]

How long will a mixed/diluted cup of oxalic acid retain its chemical property to bleach wood stains?

Perhaps not forever but it'll keep Ok in a stoppered bottle.
Remember it is a hazardous material so ensure that it is clearly labelled and kept out of children's reach

 

[Billjratt]

Pretty well forever I think.
It dries out and the crystals appear. Just re-dissolve them.

 

[SAWDOC]

Thanks