One of the issues with an older boat is the damage done to plastic by the sun. Here is how our portlights looked; they were all hazy and blurry.
The captain had the brilliant idea of using this headlight restoration kit to clean them up. He got it at the automotive store last weekend for about $30.00 and it worked really well.
The first step is to sand the plastic with this little block to remove oxidation.
Then you buff the plastic using one of the compounds and the little buffing wheel supplied.
Then you apply a UV protection and suddenly you can see out of your windows again! He also did all the portholes too. Four portlights and eight portholes only took about an hour and it was time well spent, don't you think?