Hi Rue, I'm a Perth poster, so I'm not going to mention of leaving them outside for freezing, or racoons :D
You really need to have them robbed pretty hard after extraction so they're clean, then perhaps leave them near the hive and let the bees clean them up after. Beyond that, have you thought about those olive drums from gumtree? good grade plastic, airtight lid. I think they're tall enough to get two stacks of frames arranged radially.