One of the things that has been bothering me for years is
the cloudy view out of the Bowmar hatch in the cabin. Replacing it is
both expensive and a pain, so I looked for an alternative. I found
it!   There is a company called Janvil who make
a polishing/cleaner kit that really works. With about 20 minutes of
polishing, I now have a hatch that is as good as new!
As I also have plexiglass cabin windows as well as having modified my
forward hatch with a large, curved plexiglass window, I am happy to
report this product essentially eliminates the one downside to replacing
our cabin glass (scratches).