Changing ID3 tags of music in iTunes with read-only attributes

Changing ID3 tags of music in iTunes with read-only attributes

When I add an mp3 file with read-only attributes to iTunes, iTunes does not allow me to change the file's ID3 tags or delete the file later. Removing the read-only attributes after adding the file doesn't help. If I go to the source file and delete it manually, it shows up as "missing file" with a ! sign prefixed to it in the program, and it still can't be deleted. How can I get around this? I just want to change the ID3 tags.