Velcro CA HOV stickers

Last night I spent five hours removing my old white velcro strips off from my bumpers, each strip took me over an hour. Each velcro strip is very strong and if the velcro is pulled hard, the paint will strip away from the bumper. After I slowly pulled away the velcro, thick glue residue was still on the bumper. I used Goo Gone, a hair dryer, motor oil and still the glue SLOWLY melted away from the bumpers.

Any ideas on how to remove heavy duty glue from bumpers.

At the moment I am working on a experiment with magnetic hov stickers.