I have an RFID bus pass, and my phone case has an indent on the inside for a magnetic car mount plate. The indent is smaller than the bus pass card by around an inch on all sides. I'm wondering if I can safely cut some part of the plastic off my RFID card so it'll fit inside, but I'm not sure how to tell what's all inside. How would you go about doing this?
RFID tags contain an embedded antenna (often a coil of wire). If this is damaged the tag will have its range reduced or cease to function. Unless you can clearly see where the antenna is trimming the enclosure is not recommended.