Click Empty the Recycle Bin to delete all the files in the Recycle Bin and then click Yes when you are prompted to confirm you want to delete the selected items. [Show Me]
To delete only selected files in the Recycle Bin, hold down the Ctrl key and click each file you want to delete. Then press Delete on your keyboard and click Yes when you are prompted to confirm you want to delete multiple items. [Show Me]
Tip: You might want to change the folder view to Details and click the Date Deleted column heading to sort the files by the date they were deleted. This makes it easier to delete only files before a given date.