55 ft searay Sadan bridge ( back deck cabin light lens removel ?)

[Dyna12003]

I have two 8" X like 14 inch long clear plastic light covers i want to take off and clean but can"t figure out how to get the lens off they are tight i tryed squezzing the sides thereis not where to get a flathead in. I don't want to crack the lens because i know i want be able to replace if any one has done this before please drop me a line. Thanks