How do I clean and brighten an old crate, and preserve its printing?

It's risky! I would experiment with your least favorite of the boxes - I think tung oil might do the trick - but I can't be 100% sure.

Wipe down first then try diluted vinegar 50/50 with water.

I would be hesitant especially if the writing is important to you. Depending on how old the crates are, it could wash away.

Is it a paper label or a painted, stenciled label? These kinds of things can be hard to clean without damaging the writing that you'd like to see better. If you try a cleaning solution, test it out on a small section of the writing first to see how it holds up.

You could sand it but that would remove the writing. You could oil it but that would make it darker.

Wouldn't work because you need to sand the color to remove it.

Hi! Good input from everyone. However, I am a less is more kind of DIYer. I would clean the wood with soapy water (Dawn dish detergent), a soft brush, microfiber cloths, and a magic eraser. Wipe the soap residue off with a wrung out, clean microfiber cloth. Once it is totally dry, I would seal it with a water based clear sealer. Go gently on the lettering when cleaning.

Microfiber cloths will stick to most crates unless they are really smooth. I would use old tee shirt scraps and a mild detergent like Ivory or Murphy's oil liquid soap and gently wipe off surface dirt. I have 6 of the crates and some have paper labels on end. I even gently wiped the paper labels with a damp rag and they came out fine. Old crates with writing on the wood can be lightly touched up with markers if you are not concerned about the VALUE of the crates. If you just love them and don't care about ruining the value for resale, do so. Just don't fill them in all of the way or it will look fake. Just use light strokes of marking pens to define the letters slightly after you have cleaned them.

STOP No Brush!!! I learned the hard way. It took so much of the printing off than just using a cloth.