Best way to remove moisture and mold in car?

Perhaps I should be more clear about the storage area where the car is stored. It is in a larger type storage locker unit. One issue is that the storage unit where I live in CT is pricy in this part of the country. It is approximately $200.00 a month and that is for inside storage but not climate controlled. So for now that is all I can afford. The storage locker is along a row of units on the edge of the building. There is quite a bit of temperature and humidity change even though the the locker is inside due to the drastic changes in weather up in CT. All this will be a non issue when I finish my heated garage for storage of my cars. So for now I want to be able to lessen the humidity and moisture and beginnings of mold from forming inside the car.