Escaping

I picked up some peppermint tea the other day, I'm still off caffeine, as a change from the Lemon & Ginger. In a quiet moment while I was brewing a cup, I read the box. The bit in red cursive caught my eye, I've never heard this before - cover the cup so that the volatile oils don't escape. The very last thing that I want is these little volatile scallies gambolling around the kitchen, so I'll be covering the cup from here on in.