Peel and stick tiles are made with durable adhesive to ensure a strong bond to the ground beneath. If you can pop up a corner of the tile and pull it up, you may have residue left underneath that needs to be scraped away. To remove dried glue from the floor you can use either acetone or mineral spirits. You would put either on to a rag and wipe up the dried glue. You would then follow that up with a dry rag to clean off any residue. If there is still some residue left, you can use water to wipe it up. You would then follow that with a dry rag.