side door is bent as shown on picture. tried bent it back by heating with lighter but no success. how can i know is it plastic or aluminium?

Sorry /Pardon my Ignorance:

first thing is not to  dunk in the water, till a new door,  if  you can rebend back, hot sand  is for plastics, not sure aluminum you can do that  but taking a lighter to the  door and the seals hmmm

I get a new door from DJI

https://forum.dji.com/thread-298683-1-1.html

The bent element is Aluminium, might straighten out with radio pliers but I’d take it off to hold in another set whilst doing so.

it is metal. was able to bent it back. it is ok now but scratched a litle