black spots in varnished ply

[scruff]

I have lots of tiny black spots, much like black heads in the grain of my varnished interior.

Short of sanding back all the wood (there is acres of it) is there any way of removing them?

These are not big damp patches behind the varnish but within the contours of the varnish itself.

Any ideas how to remove these?

 

[Pavel]

I've got the same problem. Tried washing them off with Cif last week and it made it noticeably better (there also was black stuff on the sponge), bur the deeply-engrained stuff remained.

 

[philip_stevens]

Try using household bleach. I used Hypo from farm outlets, that is bleach, on my cabin top rails that had large black stains, and most were removed after bleaching.

Unless your varnishing is as smooth and shiny as the front door of No.10 Downing Street, there are always small "holes" in the varnish-work, where damp and mould can enter.

 

[davidej]

Oxalic acid is the right stuff to bleach the wood.

You may want to stain it before re-varnishing as the wood will look very blond.

 

[MoodySabre]

Mine's the same. It is under the varnish. Be very careful about sanding as the veneer will only be thin. A stripper and a scrape would be better initially. As there is so much of I have grown to like it easier than doing something about it

 

[philip_stevens]

Oxalic acid is the right stuff to bleach the wood.

It was not to bleach the wood, but to kill off, and bleach out the mould. The full name of Hypo is Sodium Hypochlorite. You can get it in 20ltr drums for about £12 - against @£1 for 1ltr in the supermarket.