I show 1.5 gb being used for Messages on my iPhone, where are these and how d...
In the Messages app. Delete your messsges. iMessages and SMS messages.
There's more you can do to free up space. Upload photos to cloud based apps like Box or Dropbox. Delete emails. Especially those with photos and videos. Delete unused apps. Delete songs you may be tired of. Delete anything unnecessary from the Notes app. Delete cache wherever you can. Facebook usually builds up a lot of cache. All you can do is delete the Facebook app, then reinstall it.
Sent from my ancient but trustworthy iPhone 5.