Unsurprisingly, the Lightning cable that came with my iPhone 5s ~18 months ago is really worn - to the point where all of the rubber cable has had to come off because it had been left around for a while and had gone all sticky (sooooo gross). The outer metal sheathing is still entirely intact.
The resulting cable looks like so.
It still charges (and syncs) my iPhone perfectly. Is this at all dangerous to use (I'm charging my phone from my MacBook)?