For those of you who do not know, send spam to
spam@uce.gov. Before you send it click on details to show more information about the sender, highlight all the header information, click Control-C to copy this info to the clipboard.
Then click Forward, input
spam@uce.gov in the address, click your cursor inside the message box to fix it , type a short message like "This is spam."

and hit Control-V to copy the header information.
Then click Send.
I also send this stuff to
abuse@aol.com but do not know whether they do anything with it or not.