Here's a question:
How does a precancel effect the value of the stamp itself or is a precancel only a precancel?
I have heard the opinion that a precanceled stamp is only worth the value of the precancel itself as listed in the precancel catalogue - usually pennies. If that were true, then a "normal" collector of used U.S stamps should avoid them like the plague, right?
Case in point - this $5 Marshall (#480):
The Scott Specialized lists its value, used, at $35.00 - I think the "Rochester, New York" precancel is about 10¢.