Today when I booted my arch laptop from a usb I noticed that I have several old bootloader entries that I don't need anymore. They don't seem to be hurting anything, but it annoys me that they're there. This is how I removed them.
This gives you a list of all of your entries...each starting with something like
Boot0019 followed by the name of the entry. Identify the ones that you don't need anymore and remove them with...
efibootmgr -b 0019 -B