Cemetaries have thousands of gravestones and a lot of those are neglected and dirty. Why not offer to clean them?
There are many reasons these headstones are not looked after - relatives might live far away, or perhaps they struggle to clean it themselves due to health problems. That doesn´t mean they don´t care. You could offer a service to clean them and even get repeat business to clean them on a regular basis.
This is something that kids can do as shown by a boy in Otsego who started his business when his was in 4th grade. He charges $20 for an average-sized headstone. Even as a weekend side hustle, if you did 10 headstones in one day that equals $200 or $800 a month.