I am replacing the passenger side rear corner tail light. Do I need to clean off all the old sealant (it's a very sticky tar like substance) that surrounds the assembly on the inside of the light? If so, is using gasoline the only way to clean it off? Any advice would be appreciated!

 

Leave it.

 

Thanks. The new tail light came with a new "gasket" so I ended up using it along with the old "gasket". It should be double water tight. Thanks again.