I didn't know they took up any site resources. I've had about 300 submission notifications all years old that I was saving for a special time when I would be able to give them a closer look and enjoy them again, I've used my FA submission notifications as a catalogue of my favorite what-ifs that I've always hoped to find the willpower to dive into like a leafpile.
I didn't save them anywhere else. I wish we were notified that our messages were going to be removed beforehand so that I could have.