This is where a spray can of white stencil ink or a roll of cheap butcher paper is your friend. My local post office never has the regular priority boxes when I'm there to restock my home supply, so I either wrap the box in butcher paper after sealing, or spray it before filling with white stencil ink. The post lady knows what I'm doing, but never says anything, she just gives me that look like SWMBO does when I'm dripping coffee on the counter.... This time I hope to put them in the correct Priority Mail box. Apparently the USPS doesn't like when you mark out FLAT RATE and apply a label for 1 lb at $4.80. They still want to charge the $10.35 even though the non-Flat-Rate box is exactly the same size.