IAC Circuit Condition or Idle Speed Higher/Lower than expected

Hey ya'll, I just got this engine code check from Autozone (code: P0505) and I know for sure my car is idling at 2000 rpms, sometimes reaches 3000 and other times just starts fluctuating. I noticed how it's very dirty between the throttle body and IAC unit, and inside the throttle body. I want to fix this myself, don't plan on spending 250 bucks on a new unit. How can I get the unit off and clean it? Also, I mistakenly removed the gold plate and had the plastic gears pop-out but I quickly put it back in place and noticed it's kinda dirty inside. I think cleaning all this and the throttle body would do fine or I'll just have to buy the unit. Suggestions???