I was in the queue to buy metro tickets today and a couple of tourists were having a hard time purchasing them. I wanted to explain to them that the old one pound coins were removed from circulation yesterday. I told them 'they have been removed' instead of 'they were removed'. I think I made a mistake because it is an event that is finished in the past but somehow it emphasizes something in the present. For me, there is a grey area between those tenses and I would deeply appreciate help.