I find it much easier and more convenient to go to the USPS online and fill out, pay for, and print a label at home. You can add the tracking number (as they are now called) for free and any amount of insurance you care to pay for. Then you can pack your knife and tape the label to the box and be on your way. I always keep a small supply of the various box sizes at home (no charge from the post office). With a properly packed and labeled box you can walk right in a drop the box at the counter without waiting in line (several post office employees have confirmed this). The only thing to be aware of is making sure you choose the proper date of shipment for the label you're printing (defaults to the present day).
I guess this was a bit off topic but the reason I chimed in was because I'm rarely asked about what's in the box since I'm just handing it over. The few times I have been asked, it was just the hazardous materials/liquids question. And you may already know all of this. Mike