I have some antique tins (small, decorated) that I thought my phals would look nice planted in. I poked holes in the bottoms of them with a hole punch-as many as I could. My question, in hindsight, is, will the tin metal hurt the plant? And what if there is rust? I can definitely re-pot them in plastic and sit them into the pots if you think that is what I should do....Thanks in advance, Alley