Possible Clues:

• Obliteration of characters in rare use
• Removal taking time? Yes!
• Mark of a correction
• Puzzle smudge
• There's certain to be plenty of time for removals
• Sign of a goof
• What 32 across gives you will come to a certain end
• Sign of uncertainty
• Seems there's a certain time for removal
• Total wipe-out is certain after a time