Running shell script with no environmental variables
It seems you can prefix your script with env -i which will clear the environment before running the script:
env -i sh test.sh
From man env:
-i, --ignore-environment
start with an empty environment
Not sure why you would want to do this though...
One possibility (although it looks rather ugly):
exec -c $SCRIPT will start $SCRIPT with an empty environment. (see man bash search for exec \[-cl\]).