Idon'tknow the answer to that. I have known people to get them sprayed as the problem being its a cheap molded black rubber plastic. It can mark very easy and when you try to wet sand or polish the bumper candiscolour.
Yeah meant the door sill plastic and door pocket plastic - gonna give the mokka a good valet over the weekend weather permitting so will have a go at removing the scuffs- have loads of tins of back to black type stuff in the garageso will give those a . if that does't work gonna make everyone wear slippers!