The "other" storage is necessary for the functioning of the phone, it basically contains app data and cached files, and your offline maps too (the maps for the entire USA can take up a sizeable lump).
GDR2 cures the continual bloating of the "other" folder, but you won't be able to clear the folder itself (it'll just shrink to what's actually needed).
If you don't yet have GDR2, then a factory reset will clear any over-bloat. If you do have GDR2, then you need to live with the amount you have there, or delete some content from apps that put data into it (like delete some offline maps if you don't need them).
Without giving us figures as to what amounts you have in each category in settings->storage, it's hard to recommend solutions.
My phone has an "other" category of 1.75Gb and it's remained static (under 2Gb) for some months.