Best way to scrub my iPhones.

We recently got new iPhones and need to scrub our old Apple iPhone 4S and 5C. I’m talking a deep scrub/erasure of all data on the iPhones. Recommendations?

You can do it right from the phone itself.
Just make sure you have all your data off of it that you want to keep, and go to Settings->General->Reset->Erase All Content and Settings.

Thanks beowulff. Question, will this wipe everything from the phone in the event I want to sell it?

Not sure how securely it will erase everything, but short of using some kind of jail-broken erasing app I don’t see any other way to do it…

Quite securely. iPhones are encrypted all of the time with a random encryption key kept on the phone itself (in addition to any other encryption added).

The “erase all data” option deletes the stored encryption key, which more or less instantly makes all the data on the phone permanently inaccessible, no actual erasure necessary.

More information (way, way, way more information) and details are published by Apple here (PDF, if you’re one of the three people on Earth who care): Apple Platform Security - Apple Support

Well, that’s more for enterprise issues, for consumer wipes, advice is here. What to do before you sell, give away or trade in your iPhone or iPad – Apple Support (UK)

it’s pretty short though.

I think I’m going to run my car over these devices, or, I can just blend them.

Sandblasting. It’s the only way to be sure.