No certainty that they won't rust. The interior guts like gears are usually lubed so they'd be okay, but other parts may be affected given the right atmospheric conditions.

My Dad had a large ketch sailboat on the coast in Vancouver and it was damp there year round and especially so in the winter as it rains a LOT there. All we ever did to ward off corrosion was a 60 watt bulb contained in a simple tin housing and that seemed to work well.

You can also buy moisture absorbent devices like the attached which contain special silica that changes colour when saturated and then you simply plug the assembly into a power outlet which heats the unit and dissipates the trapped moisture and the silica medium is then ready to go again. Simply place one of these units in each systainer and set your calendar to check it every couple of weeks.

I use this method in my gun safe to protect my other toys, some of which like my IPSC Open gun are in excess of $5,000 to replace and I never worry about rust or corrosion and I've used this system for about 15 years now and swear by it.

Break-Free CLP lubricant is also awesome! (Clean, Lube, Protect).

It was developed for the U.S. military for firearms cleaning and lubrication and protection and I also use it on all sorts of other metal surfaces. It is mil spec rated. It also is readily usable over huge temperature ranges -60 to 160F

It doesn't readily attract dust or dirt and a little goes a very long way. Available at most outdoor stores like Bass Pro, etc.

http://en.m.wikipedia.org/wiki/MIL-L-63460

I have to store some tools in an unheated garden shed and anything iron like chisels and saws will definitely get those pesky rust spots in just one winter. Similarly any untreated wood will get surface mold next to no time [emoji20] Found out the hard way. Aluminium on the other hand seems to weather quite fine like my MFT and CMS-VL tables there. The MFT tabletop did get some spots on it but they were sandable away.

Just spray or wipe on Boeshield T-9 on your rustable parts and surfaces.

I live in high humidity Florida, and my shop is currently without a dehumidifier. T-9 keeps all my cast iron tops healthy and without rust during the long-durations I am away from home.  (Couple of coats of Johnsons Paste Wax works pretty well too.)

Frank

In the same vane of CLPs check out froglube. It smells awesome

Helpful suggestions!

Thanks

I live on the Gulf of Mexico now, before I lived in Michigan. The best thing I have found so far has been CRC's SP 400 and WD 40. But if you can find a space in a conditioned space that is  the best, if not check your tools every month. I lost one router and a pad sander to rust, I have a few hand tools that are not  in the best of shape due to rust, nearly 40 years in Michigan and never lost a tool to rust, two years on the coast  and lose a bunch.  It'seems funny they call Michigan the rust belt, go figure.