Removing Sticky Stuff:

Step 1: Heating.
You MUST do this process first before picking at the sticker to avoid it going really messy.
Use a hair dryer to thoroughly heat the sticky label/stripe.
Don't worry too much about the heat, you won't damage your paintwork unless you use a bloody hot-air gun.

Step 2: Peeling:
Slowly pick at the edge of the sticker with a really blunt knife or preferrably your finger nail and attempt to peel it back.
Keep applying heat. It needs to be almost too hot to touch. You'll feel the glue go tacky and hot.
Persevere with this until you have removed all the sticker surface. There may be some mank left on the bodywork.

Step 3: Removing the Mank.
Use a cloth or duster dabbed in white spirit/lighter fluid/meths etc.. and rub it maddly over the gluey stuff.
After a long while the glue will lift off. Patience!
Now you need to wash down the panels to remove any spirit residue.
Once washed you can T-Cut the areas where the sticky was to blend away any discolouration.

Job Done !

If you are doing the above procedure on glass you can use a scratch resistant scower for step 3 to remove glue deposits.
It works almost instantaneously and removes glue in a flash, much quicker than just rubbing it with a cloth.
NOTE: Don't use any sort of scower on paintwork as it will dull or scratch it.