If you downloaded some files via your iPhone, these may be some download temp files and they would eat some of your space on iPhone. PhoneClean is designed to remove corrupt files due to interrupted downloads but remain in the temp files folders. Make your iPhone run like new.
PhoneClean Pro (iOS Cleaner)
Remove Junk Files & Clear Private Data on iPhone, iPad & iPod touch
Supported iOS Devices - iOS 5, iOS 6 & iOS 7
iPhone Series: iPhone 5S, iPhone 5C, iPhone 5, iPhone 4S, iPhone 4, iPhone 3GS, iPhone 3G, iPhone
iPad Series: iPad Air, iPad mini with Retina display, iPad mini, iPad with Retina display, The New iPad, iPad 2, iPad
iPod Series: iPod touch 5, iPod touch 4, iPod touch 3, iPod touch 2, iPod touch