Piston Slap: Two Steps for Mold-Free Winter Storage
Suzanne writes:
Could you discuss cleaning off mold from leather seats? I have had to move my car from heated storage into an aluminum garage. This has resulted in mold on my leather seats. For economic reasons, I can no longer afford heated storage. Also, will a fan, dehumidifier, or something else help? This is the size of a regular-size double-car garage. I could really use some help here.
Sajeev answers:
There are several solutions to your situation, so fear not! Losing climate-controlled storage isn’t the end of the world—you only have to remove the mold and keep it from coming back with a few affordable, easily sourced products.
Step One: Spray It Away
Because mold can grow on places besides the seats, I recommend cleaning everything. This is a two-step process, and the first is using one of the many cleaning and protecting sprays available on the market. There are way too many brands out there to recommend, so I’d choose one that promises an easy way to clean off mold and then protect from future growth for months. (You will need to test the product in an inconspicuous location inside the car to ensure it doesn’t discolor the material.)
Whatever cleaning spray you buy must then be removed from the interior. You can do that with a hand towel, but there’s no better way to eliminate mold than with a steam cleaner. Steam cleaners are easy to operate, but do require a little knowledge to ensure you don’t damage the materials. Here’s a video from one of my favorite car detail YouTubers to show how it works on leather seats (and the rest of the interior).
But don’t fret if a steam cleaning machine (or service) is out of the question, as the aforementioned cleaning sprays will likely get the job done with a clean towel. I am mostly recommending steam cleaning because it is so thorough, leaving nary a streak or trace of residue on your interior. It’s a very effective solution, but it’s not mandatory.
Step Two: The Desiccants Of Modern Society
With a clean interior ready for storage, let’s now address the preventative measures needed to keep mold away. Products from DampRid (or its competition) will protect your car for at least a month, probably longer if you buy the items designed for large rooms, not closets. This is what our resident Hack Mechanic learned when addressing his storage mistakes and removing the mold that came from it.
So fixing the problem is pretty simple, if a bit time-consuming. But once it’s clean, using something like DampRid will keep it dry. You will have to check up on your DampRid, ensuring you haven’t run out of desiccant. It may not last the entire winter, depending on where you live and how much rain you get, but luckily adding desiccant is a snap.
What say you, Hagerty Community? Got a better way to remove mold and keep it from coming back?
I store my cars in my garage in the summer months in SC when it’s very hot & humid (I go up north for summer). I leave the windows down a bit with light cotton dust covers over the cars and a small fan on in the garage to keep the air moving.
I had mold develop in my 1973 Beetle when I hadn’t taken it out much one year.
Once I cleaned it up it has never returned however I mounted a 20″ fan near the ceiling that runs 24/7.
This seems to keep the entire garage moisture free.
The garage also houses my 1964 Plymouth but I tend to play with it more so have never had the same problem even though they are parked side by side.
A friend stores his cars with fans constantly moving air, which I’ve adopted. My ceiling fan runs 24/7 in the garage to keep moisture from stagnating and collecting.
Depending on the car size I use a 25 watt bulb on a trouble light in my covered, outside 23’ boat and keeps mold off. Also, there are many products for mold prevention and removal at boat stores like West Marine.
When I lived in Chicago, leather protectant / cleaner seems to do well with anything I had to deal with leather wise, never had any mold issues. In the Austin area, mold is less of an issue as we tend to stay dry.
I’m in southern Ontario Canada and store my car in a double garage which has two walls shared with the heated home. I run a portable dehumidifier all year round and the garage stays at 40%. In the winter a portable heater keeps me above freezing. A few mothballs beside each tire (or axle stand) keeps any critters from climbing into the car. Not that I have ever had any evidence of mice. Dehumidifier is the best defence against mold
Beware of damp-rid bucket styles, after extended storage the captured moisture can cause surface mold if not emptied or changed often enough. I prefer the bag-type which capture & seal the moisture.
I live in Canada where the conditions are the most erratic in North America. I have used desiccant made by DuPont for the last 20 years or more. I have used the same pouches each winter and have never had a moisture problem. I was instructed to keep the pouches in ziplock bags containing only 2 pouches. The pouches are then kept in a large plastic bag during spring through fall. They are to be spread throughout the vehicle ( dash, seats, floors and trunk). I have never had any moisture issues and have never encountered an electrical problem.
Also, consider using Bounce sheets throughout the vehicle including under the hood. Mice cannot tolerate the harsh smell plus the vehicle smells fresh when you get rolling in the spring.
I am thankful I live in the high desert where low humidity makes the are inhospitable to mold and rust
I only had mold form once (it was on vinyl), when I stored in a garage with a dirt/gravel floor, water leaks under the door, and NO roof or soffit vents. I think that having those garage vents is a lot more important than many might think. Beyond that, it would seem that those desiccants might help a lot.
On the Wet Coast, if there is mains power available, we use a marine/RV air circulator: https://www.westmarine.com/west-marine-air-dryer-with-fan-dehumidifier-120v-ac-7867518.html?queryID=31057f9a178fc454fe22fe27cab53a35&objectID=7867518&indexName=production_na01_westmarine_demandware_net__WestMarine__products__en_US
Generally prevents mildew at least.
Otherwise, yes, monthly desiccant refills are needed…
Car Capsule / Carcoon for my cars that are worth the investment, the others are left uncovered in the same garage with a dehumidifier running year round, although it doesn’t need to run much in the cold dry winter of New England.
I use these bags and they have worked well. Just remember to recharge in the microwave monthly. A diet scale is handy for measuring bag weight, which is the most accurate indicator of how much moisture has been absorbed.
https://www.amazon.com/wisedry-Packs-Large-Silica-Packets/dp/B0781BR7V7/ref=sr_1_3?crid=1QKHMI1JZHNP8&dib=eyJ2IjoiMSJ9.BKmgP8Uow8c79V7oIn-nt75S1zuy7wo926zMquLXTOZb8ZQImtz-TTAuw65E6fem88eInUVCfoqSFPyxTRYnvkbseut4-Mz-V6qb88mkbaP3iA-86WWVhDQnXPVI9-vmRCMVXOrqOn2wUgs_WCTpRh0tqQPwE6qax5dhnv7OToiqYqpHAi_XrNvTfXTt1Z0wSqrzDP9zCDi5xE3pUWTt_e7vxtSBb1uqRC34ajuDRYg.KDNeAbCVTa9E13vScVhaYr9oaXQOouxcPSQ1IACC05g&dib_tag=se&keywords=500g%2Bdesiccant%2Bbag&qid=1728421227&sprefix=500g%2Bdessicant%2Bbag%2Caps%2C212&sr=8-3&th=1
Hi, I did hang a bag with moist absorbing material on the inside of my cars and after a while those bags started to leak on my leather seats and destructed them. One seat I could be replaced by a salvaged seat, but the other two seats had to be brought to a shop to put new pieces of leather in. So be careful with those bags.
Silica gel keeps absorbing even after it is saturated, and can burst a pack. Using clay desiccants prevents this from happening, as they simply stop working once saturated.
First, air exchange. Get air through the space, and through the car regularly. Run a dehumidifier. Keep one or more windows at least partially open. Finally and most importantly DON’T COVER IT. The only time I had issues was when I was using covers. And parking the car on a vapor barrier wouldn’t hurt.