The comment I was going to submit was this:
Tending the tombstones of family was very important to my great-grandmother, and I have gone out and washed the tombstones of my grandparents and great grandparents to get the bird poop off (water and nylon brush). While I can understand that some people would rather keep the antiquated look of an old cemetery, I for one would be very appreciative if someone decided to tidy up and make the tombstones of my ancestors easier to find and read.
But since I'm already here, I'll elaborate a bit. My mom took her grandmother to the cemetery on a fairly regular basis to replace the flowers and straighten things up around our relatives graves. It was very important to her, and was perhaps a way of showing her respect and love.
So a couple of years ago, my cousins and I had the idea to go out to the cemetery and replace the flowers. I hadn't been out there in years, and had no idea what condition the tombstones would be in. So I brought a couple of jugs of water and a nylon brush with me to make sure I could get some nice photos for Find a Grave.
I honestly didn't realize that there was such a debate over whether or not to clean tombstones until today. I do understand that old tombstones have to be cleaned carefully and properly, to avoid damaging them, and I wouldn't suggest using anything but water unless you have consulted with an expert.
I've never gone around straightening up and cleaning the tombstones of others, but I truly appreciate those who care enough to do it, and do it right.
So if you haven't already, check out To Clean or Not to Clean.... Alisha provides some great tips on how restore old tombstones without causing further damage, and shows the dramatic difference that it makes.