I read an article years ago about using stale beer to de-thatch a lawn. The premise of the article was that the nutrients in the beer stimulated the growth of organisms that broke down thatch.
I had the good fortune to work for a church with leftover beer from a picnic. As good employees we tried to personally decrease the waste. I have always been what my husband always called a cheap date, so I carried home a few gallons for lawn care. Said beer delivered the desired result with many happy earthworms.