Sync itunes media folder with library I'm embarrassed to admit I don't understand how iTunes works despite having a mac for 6 years. How can I clean out my music folder (iTunes media) and then get iTunes to update? I've made substantial changes, so I don't mind just reloading the library if that's what I should do.

Also, I have a "music" folder which is not organized at all and doesn't seem to be affected by me deleting files in the iTunes media folder. Are these just copies of the songs in the iTunes media folder? Can I delete them? 

Thank you for your help, and I apologize if the answer to this question is glaringly obvious.
For every song the you import into iTunes, a copy will be made in your iTunes Media folder. If you want to delete a song from iTunes, I would suggest you do it by right clicking on the song and hit delete. Then it will let you decide if you want to remove the referente to that song in iTunes or move the file (the one in iTunes Media, not your music folder) to trash.

If you need to open a different library or reload one, make sure iTunes is closed and click on the icon while holding the option button on your keyboard and then navigate to your iTunes Media folder