I did use washi tape. I used a couple of different colors. I usually don't buy the kind of envelopes you have to lick because my mouth is always dry from my Sjogren's Syndrome. So, when I do have to lick them, I'm never sure if they're moist enough to stay closed, thus, the washi tape. It looked nicer than plain old transparent tape.
I'm glad it gave you a smile,
Proud Mom of Iraq War Vet, Please Support Our Troops!
I support Operation Write Home and the Danville, PA Ronald McDonald House