I wrote this letter on behalf of one of my coworkers, because it (thankfully) didn't happen to me.
Dear Really Inconsiderate Lady:
Yes, it's your house and your bathroom. But if you know that someone is going to be cleaning up after you, a complete stranger, please please PLEASE wrap up your sanitary pads in toilet paper or a wrapper or SOMETHING before tossing them. Don't just cram them, open and really used, into the trashcan to rot for two weeks. My coworker almost threw up. She shouldn't have to deal with your rotting menstrual blood. No one should.
If I Knew Who You Were I Would Say Something To Your Face Because I'm Leaving And You're Disgusting