Hhhmmm!
How did you arrive at the figure of 26GB for Other? In your first post, you said it was Other using all that space, but in your second post you said it was System. They are two different things.
System is space used by the iPod, to make it work. The 6th gen Touch reports the amount of System in Settings/General/iPod Touch Storage at the bottom of the screen. On my 6th gen 128GB Touch, System is 8.68GB. The size will vary, but not by much and there is nothing that you can do, or need to do, about it.
Other is basically files that have become unreadable so the iPod cannot use them. The iPod only gives a graphical representation of Other, it doen't specify how much space is actually being used. To find the size of Other, use iTunes.
With the iPod connected to your computer and seen by iTunes, look on the device:

and then look for the Capacity Bar at the bottom of the window:

When you hover your mouse over the appropriate section (as shown below), the size of that section is displayed. As you can see, my iPod currently has 3.35GB of Other. This is an increase on the previous Sync, which left about 2.74GB of Other. But I regard that amount as usual (not "normal") and acceptable.
Usually, a Sync (or two) would sort out the Other and reduce it significantly if it was 26GB. Note that you have to use the Sync feature, not Manually Manage. to sort out the amount of Other. There will always be an amount of Other, but 26Gb is excessive, except during a Sync. While a Sync is in progress, iTunes may cause almost everything to be reported as Other, but the Sync will deal with that and the more accurate figure will be reported at the end of the Sync. So are you sure that you are looking at the corrrect figure?
If two or three Syncs fail to sort out the amount of Other, you could try Restoring the iPod. However - a Restore will remove ebeevrything from the iPod and put back only the media (songs, video etc.) that is in your Library - and apps and their data from a backup. Do not use Restore unless you really, really need to. (It shouldn't be necessary anyway.)