De-badged mine today. (Well, took the Jazz badge off the rear.)
I used fishing line drawn through the badge tape then cleaned of the remains using a mixture of techniques - WD40 to soak into the foam to soften it. This then peeled off leaving a sticky residue that I took off with more WD40, then white spirit and finally Goo-gone. It was quite tenacious.
stuff!
Once cleaned off I polished the area with Autoglym to get rid of the very slight ghosting.
I'd previously removed the I-vtec badge from the rear window, the white 'lock' stickers from the front side windows, the garage's own advertising tax disc holder - not at all discrete - another garage sticker the same size off the passenger side of the windscreen, a large Dealership logo from the rear window below the brake light - right in the line of vision in the rear view mirror - and finally, a plastic dealership advert stuck to the bottom and the full width of the rear number plate.
The car looks a lot 'cleaner' for the removal of it all - and the ounce or two loss in weight must have improved the fuel consumption by a tenth of a mile or so to the gallon.
