That color that remains after the clear film comes off can be washed off with acetone, a good lacquer or epoxy thinner. Its a long and nasty job but can be completed without too much work. Traces of the color will remain but no problem covering over that after a good sanding. This nasty job is best accomplished outside as the fumes would be excessive and dangerous otherwise. I use lots of paper towels and liberal amounts of thinner for the task.

The lack of Monokote claims in the GP ARF advertising is notable by its absence. What a shame for otherwise excellent products.