I never bring it to the window. Have been dropping them in boxes for over 8 years. This was the first time I ever had a problem. It's the delivery confirmation that started this whole thing. I tried to explain to the clerk that the USPS website via eBay automatically includes the delivery confirmation regradless of my package size.
For now, I am just going to drop the single peanut in each envelope and drop the mail off in another neighborhood.
If any of my customers wonder why there is a single peanut in their envelope, I hope they are members of Net54 and they read this post.