i done this before in my mk4 astra, what you need to do is start with a coarse wet sanding paper something like 500-600 then 600-800 then 800-1000 and last sand with 2000/2500
once you done with the sanding its time to polish it, i used tooth paste although you could use a cutting compound, i did tried using brasso but i found that the tooth paste gave me a better result, also note that if you use tooth past it makes a difference which type you use, i used one for teeth whitening as this contain bicarbonate of soda which is an abrasive hence why your teeth gets whitened
remember that with this method you will firstly make the whole headlight go mat/cloudy first but with the finer polishing it will start to shine again so don't panic
once you done with the sanding its time to polish it, i used tooth paste although you could use a cutting compound, i did tried using brasso but i found that the tooth paste gave me a better result, also note that if you use tooth past it makes a difference which type you use, i used one for teeth whitening as this contain bicarbonate of soda which is an abrasive hence why your teeth gets whitened
remember that with this method you will firstly make the whole headlight go mat/cloudy first but with the finer polishing it will start to shine again so don't panic
Well I thought it was funny 
