It's been five years since I last updated Drop A Few My Way which is now at version 4.0. This script is a droplet that converts audio files dropped on it using an iTunes encoder selected on-the-fly and saves the converted files to a user-selected location or adjacent to the source file. The tracks created during the process are removed from iTunes. I keep it in the Toolbar of my Finder windows for quick access when I just need to quickly convert a file or three without having to add it to iTunes and later clean out the detritus.
This latest version of Drop A Few My Way is a general update for macOS 10.10 and later and is free to use with a donation requested.