To be honest, I am not sure if this is a valid point but it is worth acknowledging nonetheless. That said, to the best of my knowledge, a disposable tool cannot be maintained other than cleaned. Therefore, the knowhow to sharpen a blade is as useful to me as checking and replacing a vacuum tube would be to someone else.

Jeanette Isabelle
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I'm not sure whose twisted idea it was to put hundreds of adolescents in underfunded schools run by people whose dreams were crushed years ago, but I admire the sadism. -- Wednesday Adams, Wednesday