I live in a tropical country. Keeping rust away from my chisels and planes has always been a challenge. I used to spray WD40 on them and then wrap them in a plastic bag. This meant that every time I wanted to use them, I had to wipe them first and then respray them after use. The tools did not feel nice to handle because of the WD40 residue. This has all been solved with the low humidity toolbox.
Step 1: Assemble the Toolbox
The main challenge is to find a large plastic container that seals well for a reasonable cost. I like the Korean Lock & Lock type boxes. But they can be pricey. You can find cheaper copies. It's important the lid seals well.
Then you add a humidity absorber, the types that have a plastic collection tub. You remove the seal of course ;-)
Put all the tools that you what to keep away from humidity in the box. Close it and you are done. Give it a few hours for the humidity to go down.
OPTIONAL: I bought a hygrometer (humidity meter) off ebay for a few dollars just to make sure the concept was actually working. The humidity levels in the box are usually kept in the low 20% down from the ambient tropical 80+%!
I have been using this box for over a year now and the tools remain rust free! Because the volume of the box is small and the box is sealed , the humidity absorber lasts a long time. I've not changed mine yet. I have made several other boxes. This can also be used for photography equipment or any other stuff that needs to stay away from humidity.