BareMetal foil should do the job. It comes in a variety of sheens from ultrabright chrome, to matte aluminum. Best of all it's self adhesive. Depending on where the blemishes are, in some cases a simple dab of chrome paint will camouflage a sprue attachment point, especially if it's not very visible on the finished model.
The most expensive way would be to detach all the chrome parts, strip them, and send them out for replating.
HTH,
Adam Howard