The PO put in some blackout film on the back window. It made seeing out the little window worst than it really is, so being the brain surgen that I am, I took my trustly utility knife and cut a piece out of the center hoping to just peel it off, behind the small piece left some really bad residue were I can't even see out the rear window, before I pull off the rest what can I use to remove the residue?

A razor blade/goof off.
Or if you can find it 3M brand acrosol.Works the best.
I used to tint windows... It sucks getting that glue off.
Have fun. Dont cut yourself.

I like acetone for removing old glue, but you have to be careful with it.

1. Use acetone (or Goof-Off, which I think is the same stuff but in a more expensive package) only in a well-ventilated area.

2. Don't spill it on anything vinyl or plastic. These are solvents and they will leave a mark.

no need for harsh chem jus some window cleaner and a razor blade.