Please see the steps below to clear the selected sparklines or all sparklines together:
Step 1: Click the cell with the sparkline;
Step 2: Click the "Design" tab from the Ribbon;
Step 3: Click the Clear command from the "Group" area;
Step 4: The sparkline you selected will disappear.
Step 5: If you want to clear all the sparklines one time, click any cell with the sparklines and click the triangle after the Clear command;
Step 6: Click "Clear Selected Sparkline Groups" from the drop-down list;
Step 7: All sparklines will disappear.