Lots of good notions already.  Here’s my two penn’orth.

First 
All dirt is not equal.
Second
All substrate is not equal.  

So you need to do some careful observation of what you’re dealing with.  

Is the existing finish sound? - are there cracks?  will finish flake off if you
apply pressure?

What is the finish? - shellac?  oil/wax? polyurethane? 

What dirt is there?  is it ingrained, or surface.  Has the original colour
darkened?  What colour do you want it to be?  Oak is open grained, and almost
impossible to bring back to original light colour without leaving the pores
black.

On a dirty item such as I imagine this to be, I would start with old fashioned
soap and water.  Not exactly wet, but a damp cloth to remove the dust and dirt,
immediately followed by a dry cloth to ensure it dries at once.  You may repeat,
at a suitable interval.  and clean the interior if necessary.

Now go back to your findings on the finish.  It is possible to bring back old
shellac finishes, up to a point, but it takes time, and old shellac can be very
hard, needing long times to soften and allow the surface to be controlled.

If you are fortunate to have an old oil finish, then move on from water to
alcohol, or something like Liberon cleaner - based on all manner of probably
hazardous stuff, it cleans off old wax and dirt, and leaves a surface ready for
refinishing.  - just looked it up, and they seem to call it 'Liberon Wax and
Polish Remover’ nowadays.  I like it because it is so simple, and doesn’t damage
old finishes, if they’re sound.

Another simple re-finish is to pad on a few layers of shellac.  again, it needs
a sound base, and a cracked finish is tricky to bring back, but it delivers a
deep rich finish which can take a wax surface to adjust the sheen.

Oh yes - find an unseen corner first and try out whatever you are planning to
do where you can afford to make a wrong decision.


Let us know how you get on..


Richard Wilson
Yorkshireman Galoot




> On 5 Oct 2022, at 17:09, John M. Johnston  wrote:
> 
> Gentles,
> I need to clean (NOT refinish) a 1920s oak barrister's bookcase. It’s been
indoors all its life and is just dark and dingy. Suggestions for cleaning??
Thank you.
> 
> 
> John M. Johnston
> 
> “P.S. If you do not receive this, of course it must have been miscarried;
therefore I beg you to write and let me know.” - Sir Boyle Roche, M.P.
> 
> 
> 
> 
> 
> 
> 



-- 
Yorkshireman Galoot
in the most northerly county, farther north even than Yorkshire
IT #300