There is a large thread on the PCGS forums on shipping coins using the Post Office. Alot of misinformation was posted. There were claims that bubble envelopes could not be insured, and to not use them to ship coins. This is false. I work closely with the Post Office, and know several Post Office workers that know the rules perfectly. Bubble mailers can be insured for any amount, whether it is first class or priority. However, bubble mailers CANNOT be sent by Registered mail. I have filed an insurance claim for a lost coin in a bubble mailer, and had no problem collecting the full insurance amount. There are people on the forums claiming that it is best to use a box for all coin shipments. This is far from the truth. Many dealers use white envelopes or bubble mailers with no problems. Teletrade also uses bubble mailers. Some members on the PCGS forums are claiming that the dealer is "cheap" if he uses an envelope or a bubble mailer. I will mention two well known dealers who are top notch, and they both use white envelopes to ship their coins. Rich Uhrich and Brian Greer. They are both top of the line dealers, and their white envelopes work just fine. So if you are in the business of shipping coins, be sure you know the Post Office rules. As you can see, alot of misinformation abounds on coin forums, so your best bet is to know the rules for yourself. White envelopes and bubble mailers are just fine!
I have gone to a total of 5 or 6 Post Office branches, none will allow me to ship by Registered Mail with a bubble mailer. And they are very specific, and will not make any exceptions. I don't know how you managed to get past the rule, unless maybe the clerk didn't know what they were doing.
I use a little mom and pop post office / gift shop. The lines are non existant and they are next door to my bank. Never had a problem, yet.....
better check on the rules if something happens later and they deny your claim based on packaging .....
If a postal clerk goes off on some rant about something you know is wrong, just ask them to cite what they are saying in the DMM, Domestic Mail Manual. My local post office has mostly experienced folks that know what they are doing, but awhile back I ran into a trainee at the counter that informed me I could not insure an envelope. I politely asked her to refer to her DMM, well, she didn't, she asked another clerk, who corrected her.