It is very important to properly prepare computer equipment if you are going to be putting it into long-term storage. There are a number of things that can damage this type of equipment when it is put away for a long period of time, especially rust and mold, so you need to do everything you can to protect it.
Try to ensure you get a storage facility that has climate control, which will make things easier. Most moving company storage facilities have this feature and this will help to keep the temperature steady, preventing damp and mold from taking hold. A steady temperature will also stop any corrosion or cracking of the electrical components.
Climate control is not always enough, however, so ask your moving company if they have a dehumidifier available. This will remove any dampness from the air, which is particularly important if you are in a humid climate.
Some equipment can be covered with a cotton sheet to stop dust from getting in, but the air is still allowed to circulate. Plastic should not be used to wrap computer equipment or any other type of electrical equipment as it tends to trap moisture in and encourages mold. Cardboard boxes and the original packaging are better options when you are packing up your computer equipment.
If you can use a board or a pallet to lift equipment off the floor then that helps to stop mold and improves air to circulate more efficiently. Talk to your moving company; they may be able to provide a pallet.