I carry bottled water at all times, and keep my lunch in my Bastille until I get to school (then I put my lunch in my locker.)
when i was working, i would stuff everything into my Large Noe.
one day, i put a frozen Lean Cuisine in it...something Italian.
I forgot about it, it defrosted and stained the bottom of my perfect Noe...red. It eventually faded to look like a large water spot as the vachetta darkened. But I was soo angry with myself.
This was years ago, it still bothers me.