|Stanley Quad Fold 24 inch ruler, before photo
|The inside is a bit cleaner and lighter, You can actually read the numbers
|Is there even a 1 there? What is that grossness on the brass tip?
|The hinge looks pretty good, just dirty
|The brass wraps all the sides and is one piece in the hinges. Nice piece of hardware, really
|Here is my secret ingredient. Bar Keepers Friend contains feldspar, surfactants, and oxalic acid.
Oxalic acid, C2H204, is a simple organic acid. In the realm of everyday household cleaners it is a stronger acid than vinegar. It's not toxic in low quantities. Oxalic acid is even in lots of foods, notably spinach and Brussels sprouts. Bar Keepers Friend has a faint funky metallic bouquet which I don't find objectionable. Prolonged skin contact is bad for you, so wear gloves. I find it discolors the gloves immediately so I'm always glad I have them on.
|One swipe on the outside of the ruler gets off this much filth and it already looks a lot better
|Clean and dry
|Much lighter than before. I can see the numbers
|The next step is to oil the hinges and the wood.
I used what I have on hand.
|After applying mineral oil to the wood
|I have a Lufkin 386 12 inch ruler with caliper that I cleaned last week.
I use hard paraffin wax from the canning section
at the grocery store to lubricate the wooden grooves
In addition to mineral oil I have also polished these with paraffin wax. I rub some on in solid form and buff it off the brass and wood. I imagine it might slow corrosion. I think if you rubbed a lot of solid wax on one then carried it in your pocket for a day it would work even better.
For a quick touch up for the caliper you can buff the metal bit with waxed paper. I keep some around my lab to polish my wooden knitting needles.