You can probably replace the trim pretty cheaply... as for removing it, any solvent that'll take the paint off will likely ruin the finish on the rubber.
A magic eraser would more than likely work.. just do a test area (as with any new product) and do it ever so lightly.
I ended up running out in the middle of a detail this weekend for a magic eraser to remove paint overspray on the exterior kick moldings and wheel wells
i'll try the magic eraser. i tried to scratch off some pieces yesterday when i was looking for parking hoping it would be easier to remove it wasn't really. not sure what kind of paint it is probably latex water base would have probably easier. parked in street and got splashed with paint. i took it from this
to this
you can still see some white paint in the cracks by the tail lights.