I have a Master on an 04 plate with fairly bad lights, and thought from their appearance that I might have to use fine wet and dry to remove the top affected layer.
But, having found out by trials on an area out of the light path that I'd have to do it manually I thought I would try the £15 T-Cut "kit" from the local car shop. This is a tube of fine abrasive, a bottle of some sort of lacquer, and a microfibre cloth. I was surprised and pleased to find that five minutes a side with the abrasive has bought them up almost like new. (Havn't done the lacquer yet because of rain).