Cheap dust and sand protection

keep an eye on condensation build up with that.
Franco

Moisture could be handled by throwing in a silica gel packet. Come to think of it, I haven't seen one in a while. It seemed like they used to be in everything.

Silica gel will absorb a minimum ammount of moisture but needs to be dried to work again.
One problem with it is that those bags can breack easely so you end up with silica bits all over your gear.
Franco

You can also wrap it in pantyhose. They will stretch to fit, and you won't have to worry about condensation.