If it is, you can use a leather cream cleaner, Mequires leather cleaner is good. It will feed the leather and clean it removing the greasy shine. Not sure if its plastic
A cheaper option is to use Simoniz Dashboard Cleaner (in Matt finish) its got a lemon scnet which disappears after a few hours but hell, does it get rid of the shine or what! Only £6 from Halfrauds.