Goo Gone is the best I've found for removing residual adhesive. Also, it won't harm the plastic as many harsher chemicals will, including anything with alcohol. I've used it to remove a myriad of unknown sticky substances from equipment previously installed in retail locations. For really difficult areas, saturate a piece of paper towel and place it on the surface to prolong contact time.

Larger quantities of Goo Gone are available at Lowe's and Home Depot.

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Sam

84 300SD 350K+ miles ( Blue Belle )