Cannot delete files with invalid (non-ASCII) characters in their names

Apr 6, 2018
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I have a PC with Win 7 and a memory stick with several folders in which the filenames are corrupt (they are not made up with 'normal' characters): moreover some are massive (e.g., 10 gigs) even though they were originally tiny graphics. I cannot delete them by usual means, nor by the DOS del command or by say, Lockhunter (that claims nothing is 'locking' them. I have now run out of ideas. Is there a program (preferably free!) that will delete files albeit with invalid characters in their names please?