In my attempt to get my post online in time, I left out some of the specifics regarding the envelopes. I decided to update the posting so people could understand the process.
The picture above shows the reverse of the envelope (or the face of the envelope if you are sending it out without the glassine cover). The top envelope is still awaiting its liner. The bottom envelope shows the liner. The liners are made up of pages that have product descriptions only (or pages that could not be used for envelopes).
As mentioned yesterday, many times I will place the envelope in glassine covers so I can send them out without ruining the image with an address label. I simply tape shut the envelope, throw an address label on the front of the envelope, place a stamp on it and send it out.
When I send the envelope without a cover, I simply tape shut the envelope on the flap side, throw an address label and stamp on the flap side (if you are using standard size envelopes you can use a regular priced stamp since no special handling is needed). By utilizing the flap side (the reverse), the main image is unaffected. Many times, I will send out my bills with these types of envelopes.
When I use a glassine cover, I include a blank address envelope so recipients can determine if they want to use the envelope for their personal use (I also include instructions).