To clarify,you can store brass cases in anything you like.
I have over 200,000 pieces of brass, so I store brass in whatever is handy, which includes plastic bags.
I still recommend a person new to reloading 'shy away' from storing fired brass in plastic bags.
Primarily because the OP lives on the west side, there is a chance he will shoot in the rain, collected brass may be wet, ergo, moister problems.
Once he has become a seasoned reloader, this issue will have been vetted.
Hopefully this will clear up my reasoning for those out on work release.