I think it depends on the can opener you use. If it is a smooth cut you should be fine, although dealing with kids you never know. My DS would touch it in just a way that it would cut him, just because I told him it wouldn't.
I agree talk to the teacher and show her what you are planning on doing then maybe she can give you the go ahead. Scoutpup has a good idea with the sourcream containers! Those are so cute!
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Caren