Chewing on plastic

My cat has a habit of chewing on plastic bags or other soft plastic things. She only really does it around meal time and she doesn't seem to be trying to really eat/swallow it. I try not to leave anything out but she is like a wizard and always seems to find something.

I have talked to my vet about this and looked online but haven't found anything that stops this behavior. It's not really causing harm since she doesn't seem to be trying to injest it but I worry that she will someday and it will cause an obstruction. Looking for any tips that have worked for others.