The grills are very easy to remove with a small paperclip. Just unbend it so you have two pins pointing down, and fit one inside a hole opposite the grill. Then turn and it pops right off.
What is being said in the last post just doesn't make any sense. There is no way you can remove the headband without removing part 22 (called the lid in the manual) and then removing the screw that holds the base of the headband to the pivot assembly.
The first time I removed the lid from my Q701 it was a real pain. The hole on one side helps, but they really should have made one on the other side too. If you place a thumb on one side and your index finger to the other, you can squeeze the whole cup, including the part bellow the lid. Place your fingers low, touching the silver ring. Pushing there will unclip the latches. Keep in mind that the lid is clipped to the headband too, so pull it from the bottom up. You can unclip it from the headband once the latches are free.
I found that the base of the latches is too wide to fit between the cup and the pivot mechanism inside. This makes the first disassembly really frustrating. One of the latches could not be set free because there was not enough place for it to do so. I had to force it out by twisting and wiggling the lid. Once I figured the cause of the problem, I filled off a bit of this latch, making it real easy to remove again.
The outer casing is very soft plastic, and can be damaged easily with metal tools. Be careful if you use something to pry, as it may damage the housing. Also don't tighten the screw of the lid too much, as it'll crack the plastic. Talking from experience here.