A few thoughts:
- Lemon Pledge has been a standard for decades, but I have not used it since I stopped being able to find it in the brown can. There are now a lot of "lemon pledge" products. DO NOT use the pledge multi surface cleaner as it contains alcohol. It's also worth remembering that Johnson and Johnson does not make it as or market it as a plexiglas cleaner, so they are under no obligation not to change to a formulation that contains alcohol or ammonia. Finally, all pledge products contain silicone and if it gets on the rest of the plane, removing it is a real bear if you ever need to touch up the paint.
- Prist is designed for plexiglas and it works fine.
- Plexus is also made for plexiglas and it also works great (less prone to leaving a haze than Prist IMHO), but it's expensive.
- Plex-All has pilots who like it, but I've never used it personally. It's about half the cost of Plexus.
- ClearView works well and it's the plexiglas cleaner I've been using lately. They also make a polish/protectant that helps remove and fill any scratches.
- Never use a cleaner that contains alcohol or ammonia.
- Water and some time to let it work, works great for softening and removing bugs. I use water and a wet microfiber cloth to get things started, let it sit 10-20 minutes then finish up with a cleaner and a dry, clean micro fiber cloth.
- Whatever you use, wipe back and forth, not in circles. Wiping in circles will eventually create a halo effect on plexiglas.
- Microfiber cloths are an improvement, but be sure it's clean. Don't use a microfiber cloth with polyester stitching, as it can scratch, and remove the tag as it can scratch plexiglas as well. Old school cotton diapers still work great if you can find them.