If you have a chainsaw handy, cut in a tic-tac-toe board, about 1 inch deep if you can. Water daily. Douse with Epson salt periodically. As the top layers rot, scrape it down and repeat.
Just remember, as the stump rots, the roots under the lawn will rot also, so you may experience sink holes in the lawn.
"I believe there are more instances of the abridgement of freedom of the people by gradual and silent encroachments by those in power than by violent and sudden usurpations." -- James Madison
How about Ammonium nitrate and a match?
Disclaimer: Only kidding. Don't do it.
Peter1469 (05-21-2021)