grub2 - How to delete kernel entries in the Grub 2 menu whose kernels are removed?

I executed the shell script given in How do I delete kernels from a server?. It deleted old kernels but not their associated kernel entries in the Grub 2 menu. For example, the shell script did not remove the Grub 2 entry »Ubuntu, mit Linux 3.2.0-24-generic (Wiederherstellungsmodus) (on /dev/sda8)« and »Ubuntu, mit Linux 3.2.0-14-server«.