Got a nice tight little No. 32 1/2 (evidently a Stanley knockoff) brass and boxwood folding rule. (12" plus the 3" sliding extension)and would like to clean it up a bit.
What is your best advice on removing years of discoloration but not removing the markings? 

I have learned the hard way over the years to do the minimum amount of cleaning. blow the dust off, use a damp cloth on it, and address any active corrosion. I think old tools should look like old tools. Thanks
Bruce

Being a little OC, I cleaned it just a bit with some fine steel wool.  In a case like this, I put one of Mrs. Northwood's old magazines on the bench.
Tear off a dirty page, and you are good to go, over and over.  I saw just a bit of dust/residue on a page, and the rule showed just a bit of improvement.
Put it in a box with some old Stanley marking gauges.
I rescued it from a steel box under a table at a junk show.  Traded it for a Leonard refrigeration rat.  They never appealed to me.

Dawn dishwashing soap does wonders , no damage to anything I've used it on.
WD40 works for stained items, never any problems

I'll try the Dawn on something else first.  See what it does.
But WD-40?  What will it do to boxwood?

Quote from: Northwoods on December 09, 2019, 03:55:55 PM
I'll try the Dawn on something else first.  See what it does.
But WD-40?  What will it do to boxwood?

WD40 is Stoddard solvent and " fish oil"
It may darken it a bit and leave a shine , but it usually evaporates and it's just clean.