I need to reduce storage and dont know how???

the one you cant access is for the tablet,you dont play in there,delete apps to gain space

Start by checking storage space available. some older versions of android have a nag of accumulating useless data in some corners of the system. You may not be able to see what uses the space, but at least it will tell you if there is space or not. To help you, i need to know if there is actually any storage left or not.
This can be found in "settings -> storage"

Note: Internal storage = the onboard storage from the factory. memory is the RAM, nothing can be saved here. So if you have an EXTERNAL micro sd put in, please provide this information.

Hi
If the machine is returning "out of storage space ", then you need to remove ether data or apps (or both) so that the machine has some storage space with which to work.
Alternatively, you can add in an SD or SDHC card or micro card, thus giving you extra storage as 4Gb is quite a small amount for processing.
Hope this is helpful, if so would you please register that with Fixya
Cheers

you need to go into the app management menu and move apps to the card. some won't allow you to do that but many downloaded apps will.

you will need to reduce space, delete unwanted files items and create space for new apps, alternately see if you have a microsd card (external storage) which is not full.

See if this helps: Storage Powered by Kayako Help Desk Software

It's from the Nextbook site and talks about the caches you mention.

Most likely your iPad is full... of pictures, videos, music, etc. Visit the Settings app, tap General, then Usage. In the STORAGE section at the top, you'll see how much of the storage is available on your iPad and how much is used. If the available number is small, you need to remove stuff until you have enough to handle incoming video streams (YouTube, for example).

The STORAGE section also identifies the apps that are using your space - if Music, Photos & Camera, or other apps seem to take a large portion of the space, either remove some of the data associated with those apps (pictures, movies, music) or remove apps themselves (apps you don't use don't need to be taking space on your iPad).

Portable devices aren't meant for large permanent storage. You should save things you intend to keep forever on your desktop device or in the cloud.

Hi Anonymous,
This might help you, just follow these:
1. Go to your iPad's home screen by clicking on the home button. Click on Settings to access your settings.
2. Go to General in Settings and click on Usage. This will allow you to manage your storage, as you'll see a list of what's stored on your iPad. Look at how much storage you have available. This will inform you how much you need to get rid of, but not too much because you still have plenty of space.
3. Click on Manage Storage to start managing your storage. See what apps you have and how much space they take up. If any apps take up a lot of space, and you don't need them any more, you know you need to delete them.

4. Delete unwanted apps. To delete an app: •Tap on the relevant app in the list. You will see the button Delete App. You will also see the app's size and its Documents and Data usage (including data cached for quick access).
•Tap on the Delete App button, and the app will be deleted. •Note that the apps that come pre-installed (such as the Music and Videos apps) cannot be deleted.
•Take care not to delete any apps you need, especially for work. Instead, make room for them by determining which apps you no longer use or want (such as games, PDFs or other items you've finished with).

Tablets have internal storage and external SD cards (optional) storage. Apps will download to the internal storage. So under Settings > Storage make sure you have space on your internal storage.