A couple months ago a well meaning teacher gave me tempera paint she had found in her room. I was happy to take it...didn't think twice.
It seems that the tempera paint was a bit older than I thought. It had fermented...and the bottle exploded!! ALL OVER THE OTHER PAINT...TO THE NEXT SHELF...AND ONTO MY COUNTER TOP. It don't look too bad...but it smelled HORRIBLE! I had to wash all the other bottles and the cabinets out!