Debadging
To remove the badges from an E30 is a 15 minute job and cleans up the back end of the car in my opinion.
What you need is a piece of string or fishing wire, some rubbing compound, some polishing compound, some tar remover, some polish, rags and a kettle.
Boil the kettle and pour the hot water slowly over the badge, this softens the adhesive.
Then using the string in a sawing motion get behind the badge and saw away the adhesive.
Now you will be left with the partial remains of the adhesive.
Now using the tar remover and a damp rag begin rubbing away the adhesive, this is the hardest part of the job and I even resorted to picking away with my finger nails, but unless you are very very careful do not try to shortcut by using a stanley knife blade, keep working at it with the tar remover frequently adding more of the product and rubbing away. After 10-15 mins you should get rid of most of the adhesive.
5 mins
10 mins
Then once you reach this stage apply a little rubbing compound with a damp cloth and rub away the last remains of the adhesive. Then using the polishing compound and a damp cloth polish away the different colour paint under the badge so it matches the surrounding paint - this is becasue the area under the badge will not have weathered as much as the exposed paint work but a few minutes polishing will bring it back, and finally a couple of coats of normal polish and thats it.
before
after