Create a diagonal corner-to-corner cut across the cork tile. Make a second cut in the opposite direction to form an "X". Hold a chisel at a 15-degree angle to the cork tile, slide the tip of the chisel into the center of the X and lift the chisel handle. If the tile doesn't lift up without resistance, use a hairdryer on high heat to melt the glue underneath and slide a blade or chisel under the tile and slowly prise loose.