Any advice on selling a cemetery plot?

Went to visit my mom yesterday and she said she owns 2 plots in a cemetery near Atlanta that she wants to get rid of by any measure, just tired of having them I guess. She said she called the local funeral home and they don't do that, then she called the cemetery and they said they don't do buybacks but she could donate them if she wanted. So now she's given this over to me.

I did about 2 minutes of googling yesterday (will start actively trying to look into this in the coming weeks I guess) and I realize I need to look up state laws on selling them, but other than that does anyone have any experience with this? I don't really want to list on one of those "pay a fee and list your plot online" site, and I'm not sure if posting on craigslist and the like would be good.

I believe I have the deed to the plots, but they are in my mom's parent name. Am I going to have to track down a will or something to show that she owns them now?