When I changed to my BP emblems, I used De-Solv-It and Windex to clean everything off before adhering the new emblems.
De-Solv-It works awesome, better than Goo Gone simply because it's not as syrupy and it comes in a spray bottle (even though it's wiser to spray it on a paper towel and wipe with that). It also had a GOOD smelling citrus scent, Goo Gone smells nasty sometimes.
I used it to get some crud off my windows too. I went to an automatic car wash (which fucked my rims up! Never went again, and I never will again, in any car, auto washes SUCK!) and the spray on "wax" they use fucked up my windows. It left these seemingly impossible-to-remove dots all over the window. NOTHING would take it off, not Citrucal, not Goo-Gone, not Windex, not Simple Green. De-Solve-It took it off with a single application, I just had to let it sit for 5 minutes and it all came off.
Just spray a little on a papwer towel, wipe it on whatever's dirty, and wipe it off with a clean towel. If it doesn't work, spray more and let it sit for a few minutes. Then use Windex or water with vinegar to clean off the De-Solv-It because it is petrolium based, and it will leave a film if you don't clean it off.
It does not destroy paint either. Before I clayed my whole car, the areas I had cleaned with De-Solv-It when I changed my emblems were noticably cleaner and shinier than the areas I hadn't touched on the trunk.