Growing herbs in containers

I like to grow plants in unusual containers. I recently planted some herbs in a strainer sort of device that I wasn't using. Of course it now is all rusty from being outside. It occurred to me that perhaps I shouldn't have edibles growing in rusty containers. I have other herbs and vegetables growing in rusty containers.

I've read you can coat rusty containers with polyeurethan (sp?) or something like that but I worry about that being in contact with edibles more than I do the rust.

What do you all think?

Thanks
Gwen
P.S. Keep in mind I'm still alive after many years of this sort of sloppy behaviour.

Personally think I'd prefer the rusty container.
It could only add iron to my plants and my health.
The metal is more natural than any poly~whatever.