It’s possible but not likely easy or practicle. It depends on how the flat panel monitor was interfaced to the computer. You may find it easier to sell those screens as parts to some part who is buying them. Check the internet for those who are buying old laptops with working screens, etc. You may be able to sell them through that channel.
It would otherwise take a technician time to test the interface. The cost of that time would likely be more than the value of this stuff used. I share your desire to not want to junk a part that still works. Best of luck finding a place for those flat screens. Pity you could just add a tuner and turn them into TV sets!