Some doofus on a college campus somewhere poured some Oxydol detergent into an envelope and mailed it to her house. And then bragged to his friends about the great blow he just struck against the fascists.
I thought it was powdered sugar. I have not heard what the first attempt was.
It should come under the same genre that selling an undercover cop a bag of sugar that was supposed to be cocaine. Lock the bastard that sent this to for 30 years and see if it still a hoot to him.