Coffee in the lav???

So I was running late to a flight because the jet bridge broken and we had to climb down the back end stairs on a DC-9. There was no time for a pit stop in the airport. Once I got my bags put in place I hopped into the lav for a quick pit stop. I finished up my business and put the seat lid down. The strangest thing was laying behind the seat lid, a bag of coffee grounds. I pointed this issue (at least I thought it was an issue) out to the flight attendants. They explained to me, that this is done some times to reduce the smell from the lav. Seems like a real good way for the airlines to spend their money... Using coffee as a lav deoderizer. Must be cheaper than actually cleaning their lavs!