Why am I almost out of device memory? And how can I get some back?

I have a Vz Note 3, rooted, stock, still on Android 4.3. 32GB device memory. From Menu, System Settings, Storage:
Apps 2.25GB
Pics, Vids 72.79MB
Audio: 200KB
Downloads: 296KB
Cached data 480KB
Misc files: 29.33GB (WTH!)
Available space: 413MB

Tapping the misc files, shows System memory at 29.08GB (again, WTH!), thumbnails at 164MB, then waze at 18MB, and down from there. Not much I can do here.

Admittedly, I have a bunch of apps (~175ish), but I don't think they're the issue. Using DiskUsage, the Storage card/Apps folder shows 1989MiB. The top 50 apps total 1459.

So... Sorry for the vague question, but where's all my space? And how can I get it back?

Any suggestions/guidance is appreciated. Thanks in advance.

The place I would start is with caches. The Facebook app has been known to hold on to cached data, fill up and then begin to overwrite. Many of your other apps may also be holding onto cache data. You can try one of the cache removal tools from Google Play but check out the reviews and try to only get one that deletes caches and not one that does a hundred other things. You may also be able to reduce your load by checking your email app. Some apps save copies of emails sent from they device on the device. Maildroid for one, allows you to choose whether to save sent items to the server or on the device. I've run into this very issue when just a few emails with attachments were saved on the device instead of the server. Email drafts saved on the device can cause you issues also. You may want to check for those as well. Obviously uninstalling apps will help or if you can move anything to an SD, but I've found those to be less effective than just doing a little housekeeping.

Thanks VidJunky. I cleared the cached data in the system settings, and for good measure I cleared both the cache and dalvik cache (via SafeStrap). Gained a couple hundred meg, but nothing of significance.

I don't have the FB app, so no issue there. And I clear the browser cache on exit.

I get bombarded with emails (who doesn't), but try to manage it. And they shouldn't be GBs of space regardless.

I use Clean Master, which helps with some minor stuff, but I must be missing something big. :(

If you don't have an auto delete setup on your texting app, those can sneakily eat up a lot of space over time. Make sure you're checking that too.

Under the system memory, of the 29 taken up I think about 8 to 10 is for TouchWiz, which is Samsung's version of Android.

Thanks Moondriver. Been there/done that. I don't have too much there as a rule, but cleaned it out thoroughly recently.

Thanks Golfdriver. I've been figuring all along it was Sammy and Vz conspiring against me. Still don't think I should have that little free space though. I've been debating a custom ROM for a while, mainly just to free up said space. I'm ok with TW, and very much like the Note. I may well have to shift my focus to finding a fairly stock ROM that keeps the Note specific stuff functional. And Gates thought 640K was enough... :)