boil hot water in kettle, pour down badge/s, get an old card such as a blockbuster card down rear of badge and prise away. Will come off but may leave small residue/glue heat that up and pick at it. It will come off eventually. As you have a yellow one, you may need to t-cut it as the paint behind badge will be a lot brighter than existing paint on car due to it not being exposed to the elements
You could use old badges again, put some sealant etc on rear, but they will probably be faded so you can get new ones off ebay etc