Two things come to mind....
If it has absorbed into the plastic it has to soak out...maybe spraying with Febreeze and allowing to dry...then doing again and again until the plastic has absorbed it and is saturatured.
Kilz sealer/primer(oil based) works wonders for me...then paint with a pretty gloss paint....Sealed properly the odor won't get out....
Too great a find to just throw out because of the odor...something will work...