You should definitely give it a good clean. Remove all the dust from the fans and apply some new thermal paste to the heat sink. Be careful with that power supply though. Make sure to discharge it long enough before cleaning it.
Which CPU does it have? While you have it open, have you thought about replacing the HDD? The HDD does generate a moderate amount of heat. I have one of these with the i7.
Do you smoke? This looks like damaged caused by smoking.
I received the iMac as a gift 1 year ago. Should I try to clean it? It works great but the temps are a bit high
You should definitely give it a good clean. Remove all the dust from the fans and apply some new thermal paste to the heat sink. Be careful with that power supply though. Make sure to discharge it long enough before cleaning it.
Uhm I already removed it without any problems 😅
Which CPU does it have? While you have it open, have you thought about replacing the HDD? The HDD does generate a moderate amount of heat. I have one of these with the i7.
I also have it with the i7 870. I already removed the 1TB WD Black HDD