There used to be a tutorial here (my bookmark is still RACKSHACK!) about how to correctly remove old kernels from the /boot folder to free up space. But I can't find it anymore. Can someone please post how to remove the excess files from the /boot folder? If I remember correctly, you can't just remove them but instead need to uninstall them...

Can someone help or point me in the right direction?

You can rm the kernels, and then edit the grub.conf to take the specific entries out. Just make sure you make a backup of the grub.conf before editing and that you don't remove your default, the original kernel installed on the machine, and maybe one of the first most previous kernel. This will ensure that, in the event of an issue, we have a working kernel to boot from.

The proper way of doing this would probably get a list of the kernels installed on the machine

compare those entries to your current kernel:

and remove any of the kernels that are older than what you are running