I personally like to take them out compleatly its pretty easy. Make sure the engine is not hot so coolant does not splash out of the lines. I used CRC TB cleaner and a rag (you will need to do a little scrubing not just spray the cleaner). Make sure not to move around the flap too much, just hold it open all tne time. There is 2 hoses, 1 connector, and 4 fasteners (15mm hex if i remember right).
I hope thats helpful