I own a 25 year old home with a garage under the bedroom. My tools are
rusting, just by being stored in tool boxes in the garage. I live in
Nebraska and have never had this problem before. Moisture gets in in the
winter from snow carried in by my wife's car. In the summer, the warm
outside air seems moist. A relative humidity meter (I purchased and placed)
on the wall rarely goes as low as 60% and is usually above 70% and sometimes
above 80%. I can buy and use a dehumidifier in the summer (I am told trying
to use them in the winter can damage the unit).

Do I have other options? Are there granular or other products that will
draw the moisture out of the air? Is there a reasonable way to minimize the
moisture my wife's car brings in (or isn't this the culprit)?

Thanks in Advance.

Respectfully,
Andy