Ignoramus21381 wrote:

Thanks to all. Yes, obviously, the lids would breathe. The question
is, would desiccant be able to take care of relatively little moisture
that enters the boxes during said "breathing".

No!

In the shortest of terms, it might be satisfactory. The dessicant has
a limited amount of water that it can absorb, then it is just so much
filler.
If you expect them to last, airtight is the only way. Vaccuum would be
even better. Dessicant in both cases.


That stuff is kind of valuable on a per tool basis. I placed moisture
measuring pieces of paper that came with desiccant, in the boxes, I
will see how they change.

They will look really good for quite a while, then rust.

Spraying them all with oil, is not very practicable.

Then that narrows down the options, doesn't it.

I may clean up the shed a little and move them into the shed, and
maybe add some safe heating to them.

That will improve things somewhat, but you still will not have
alleviated the issues that come of atmospheric moisture.

Cheers
Trevor Jones