How do I clean OLD MILK CRATES?

I have three (80? year old) milk crates they are in good condition but are dusty dirty and have several water marks. I would like to clean them, and apply a coat of oil polish to preserve them. I need to clean them in such a way as to preserve the black ink screen printing to keep them authentic.
Any suggestions?

I don't think they are valuable, I just want them to look better so I can use them upstairs.

Try Dawn Dishwashing detergent and a soft sponge. If it works for getting oil slick oil off birds, it should work for you. My cat fell into a pan of old oil my husband had drained out of the car. I washed her with Dawn and she was fine.

use a vacuum and get the dirt off them first....the watermarks are part of the crate and probably wouldn't come off anyway. Oil polish will turn all the wood dark as it soaks in at different rates because of the watermarks and the ink.

Use a wire brush on them to get the loose rust off. Use spray paint. They'll look great.

When you clean antiques you strip them of their value. I would carefully wipe them down or vacuum them and perhaps rinse them with a mild soap, then plain water. If you do anything else, you will ruin the value.

hey this might seem simple but if you just hose them off and let them sun dry fairly quickly it ought to do the trick no soap or anything that could damage the wood. im not sure if it will do much for the existing watermarks but the stain should cover that slightly