Getting rid of "other" data???

Arrrrrgggghhhh! Here we go again. A horribly aggravating issue with my iOS-units (this time iPad Mini Retina), and Apple takes NOOO responsibility for it. "Let´s not offer our customers any actual support at all! Let´s have our customers help themselves instead, so that we can focus on making money!"

How do I get rid of the incredibly annoying "other" data that currently takes up 4 GB of space? I more or less only use my iPad for movies, playing backtracks when I´m performing live, and for GPS-navigation at sea. None of which should cause 4 GB of unidentifiable data to end up in the "other"-category. Erasing and restoring from backup does NOT work.