I've had to use scotch tape on every envelope: the two side do not seal cleanly nor do they remain stuck..It is going to take a long time to use all 500 of these poorly constructed envelopes. Next time I will certainly try some other brand.
I bought these envelopes for my husband's charity mailer. He printed mass quantities through our HP inkjet printer but has better luck with the single fold style envelopes. These jammed repeatedly because of the additional fold. They're fine for hand addressing but I don't recommend them for a small home printer.