Open up the airbox by unscrewing 8 x Phillips screws. If it's the same as mine you'll need to take the engine cover off by undoing 4 x bolts first.
Lift out the air filter and rubber seal. Get yourself a tin of carb cleaner and it'll give you instructions on the tin about how to use it - basically just spray a little around & down past the butterfly while someone is revving the engine.
I don't know anything about a gasket, if it's a more thorough clean than this you're after, that's something different. Hope this helps anyway
enc, yes there is a gasket and no i didn't replace mine, it seemed ok and in tact, but i will get around to getting a new one though. It sits between the body and the inlet manifold, pull them apart very carefully and look, if it looks like it will break, put it back together and go get a gasket. Then again, get a gasket first.[^]
I just cleaned the butterfly valve with carb cleaner gave it a couple of squirts cloth underneath to catch the excess and then dryed out the inside and around the valve, This seemed to do the job all I had to do was remove the rubber connecting hose coming from the intercooler to get to it and bobs your uncle idles alot smoother now.
Did mine at the weekend too, managed to get it off without damaging the gasket, gave it a proper clean with carb cleaner and refitted / performed TBA on Vagcom. Seems a lot smoother at idle, no lumpy acceleration and no error codes have re-appeared which is a bonus 
I've done a throttle body clean and a maf clean this weekend and car now seems to want to idle at 1200-1400 sometimes dropping to the proper 800. I did try unplugging the battery for about half an hour but still seems to do it. Any ideas?
Have you done the Throttle Body Alignment (TBA)? this works on some engine codes but you can try it, turn the key to the ON position where the lights on the dash light up but dont turn the engine over, wait atleast 3 minutes and TBA should be done. Then you can start your car as normal and check your idle. If you want to make sure TBA is done you can turn the key on the ON postion open the bonnet and put your ear near the Throttle Body, you should hear a buzzing noise and after a couple of minutes a click sound, thats the end of TBA.
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