I am cooking for a large group and am trying to do as much as I can in advance. One thing I would love to do in advance is chop several onions. I have done this before with a single onion; I stored the chopped onion in a plastic storage container (sealed with the lid) in the fridge. About 6 hours later, the smell of onions was very strong both in the fridge and on everything that was in the fridge. I can't imagine it with 4-6 onions!

What can I do to avoid the smell, not ruin everything in my fridge, but still be able to do the preparation 6-8 hours in advance?