Thursday Morning Riddle
Thursday, September 3rd, 2009I’m a cartridge unloaded; a key that’s unfiled;
I’m a check with no limit; a face that’s just mild;
I am paper unblemished; in Scrabble, I’m wild;
And according to Locke, I’m the slate of a child.
I am a __________.
UPDATE: Riddle solved by Ms. Maddy. See comments for answer.