How to "uninitialize" a variable in Karel?

So I am having an issue with variables staying initialized, I am calling one of my KAREL scripts and giving it values to its variables, some of the variables are optional and when I dont give them any new values, they keep using the values from the last call where they had a value. I am guessing that this is because KAREL saves the values in a .VR (?) file and uses old values if no new ones are there.

I am using UNINIT inside my code to check wether the value is initialized or not, but that breaks, because once I give it any value, it stays initialized, is there a way to "uninitialize" a variable in karel? Like var = null or something?

P.S. I just found the %UNINITVARS directive in the Karel manual, but it doesnt seem to help.

So set_var with second parameter being uninit_Value will uninitialize it?

Ah so you are using another uninitiqlized variable and set its "uninitialized value" to the variable that you wqnt to uninitialize

Thanks it worked. However Im curious why the %UNINITVARS directive didnt work, I also found a KCL command DELETE VARIABLE and it also didnt work, I even tried to delete the VA and VR files but they are protected, god knows why.