The most secure way is attach a wax seal to an envelope is using a pro-grade adhesive sticker. Those of you that got the fall box have some of those (there will be more coming in the Valentines box). You can get them here on my website if you don’t have any. The glue dots in the holiday box were not intended to go through the mail.
The second most secure way to attach a wax seal is to pour it directly onto the envelope.
Once you have your seal attached to the envelope, deliver it to the post office and let them know that the letter is non-machinable or needs to be hand-cancelled. This means that your lettering and wax seal will not go through the machines at the post office and will be handled by hand. Postage will cost .88 to send a envelope this way.
In the past I’ve sent letters with wax seals that I poured through the mail and DID NOT use hand-canceling. None of the wax seals arrived. I have also sent a wax seal with a pro-grade adhesive sticker and it did arrive on the envelope, but was scuffed.
If you want your seals to arrive in tact, either use hand-cancelling or use an outer envelope to protect the wax seal.
Let me know if you have any mailing questions below!!