You're only deleting the save folder within the game folder right ? Because the real saves are more likely to be in your local disk within a hidden folder named "Renpy" (if you're on window but it must be the same on other systems I think idk) which is a little way away. Path must be : local disk (the one with your system in it) -> folder "users" -> then the folder named after the alias you gave to your system -> AppData (hidden folder, you have to unhide those just google it if you don't know how) -> Roaming -> Renpy, and there are the folders with the saves from all renpy games you've played. That's where you delete the saves or copy old saves (if you get a new PC with a new system), doing so in the game folder of the game doesn't do anything.
Anyway, searching for it is probably more annoying than simply saving on top of old saves though, especially if you've never went there and try to follow my clumsy instructions.
WIN
+R
- write
%appdata%
and press enter - click folder named Renpy