If I'm not mistaken, WD40 stands for Water Disburtion, formual #40! It does work well for removing gooy, sticky stuff, and may for a while give a shine to your glass. The base oil used is fish oil! In the sun, it might turn yellow, however.
I bought a used fiberglass boat a few years ago. The hull and deck were in pretty bad oxidized condition. I used a marine product called Fiberglass Restore and it worked well. I will admitt, using a power buffer makes the job a lot easier!
If your glass is oxidized, or turning yellow form the layers of wax, you probably would have best results by buying a slow speed power buffer and using Final Buff auto polish to bring back the color and shine.
Yes, your bones are going to ache for a few days!