I just took the stickers off the back of the seats which says "passengers may not sit in back seat area, etc..." I used prep-sol and removed all the glue without any damage to the plastic. However, you can still see a rectangular outline of the sticker when you look at an angle.

Also tried a little Goo-Gone - no effect.

Any suggestions to make it 100% or not possible?

 

Seems like you've done all you can do. Just leave it and check it out a day later. I'll bet you can barely detect it.

 

i leave them on since they match PCCB yellow & band on steering wheel perfectly.

 

goo gone took mine off 100%. You must have not scrubed hard enough. use a little alcohaul then goo gone again it will go away.

 

I just used wax and it came right off. Much safer than goo gone IMO.

 

WD40.. comes right off.