I just had a talk with my Post Master here in the town I live. I have been sending my flowers in yellow envelopes. She asked me to try and remember to take off the metal tabs off the back. They get stuck in the machines and they have to process them by hand. If you don't take them off then you need to cover them with a sticker or tape. I am not sure if this is true for all post offices but I thought
I would pass on some helpful info. I hope every body is having a good day.