How to get sticker residue off the back of iPad mini?

I just bought a used ipad mini (1st gen).

It has a huge sticker on the back that covered the whole back of the ipad.

Well, after I pulled it off, the whole thing is covered in sticky, gluey residue.

What is the safest way to remove this?

I know some people say wd40 or goo gone but I have heard horror stories of these things destroying products.

I appreciate any help!

(I tried just rolling it off with my fingers but it is way too sticky)