clearing saved data

so i'm trying to make a game with tons of hours of gameplay, and i want to add a way to save, but i can't find a way to only load saved data if there is any, aswell as a wat to clear data

System.save(Name,value) is how to save

System.load(Name) is how to load data

i know that, i just want to know how to "clear" it

You could set the save value to the default, but other than that I can't think of anything