Two metal washers fell inside my monitor while installing a monitor arm

Hello. I’m Japanese, so I’m using a translator for this post. This is my first time buying a monitor, and it’s also my first time posting anything on Reddit, so I’m sorry if I make any mistakes or if something is unclear.

I’m currently using a KEY TO COMBAT H24T7 monitor. My Amazon Basics monitor arm arrived today, and while I was trying to install it, two metal washers accidentally fell through the VESA mounting holes and into the monitor.
In this situation, should I have the monitor opened up and remove the washers, or is it safe to continue using the monitor as it is?
(I’ve decided not to use the monitor arm anymore and will go back to using the original stand that came with the monitor.)
If I should remove the washers, how can I safely open the monitor and remove them?
I’m sorry for making a post without knowing much about monitors. I would really appreciate any advice or help.