Are you wanting to clean a widescreen that is fundamently OK but just dirty , or are you after do a complete renovation job?
If the former then John's suggestion above is good , but there is always an area between the two pieces where they overlap which is difficult to access unless you remove one of the pieces.
If the latter then is best to get specialist advice , crazed and cracked perspex is not easy to recondition, and often it is better to start afresh rather than waste hours on a job that will yield disappointing results at best.
