If this "film" is anything like the teflon coating that's on the throttle body, its worthless. It has been shown that the teflon on the TB does very little to prevent buildup. Many people have cleaned the TB with positive results, so I think its safe to apply the same logic to the IAC. If this "film" is altogether different, then maybe different rules apply.
I also look at it this way: even if a cleaning isn't good for the IAC, it will at least buy some time before it must be replaced, since if you can't clean it then what else can you do with it?
EDIT:
Originally posted by mycainsbroken:
two if you have moosing it will make it louder and or create the moosing which makes sence
In my case I cleaned out my IAC and it eliminated the slight moosing I was experiencing. Immediately after I cleaned and remounted it the moosing was horrendous, but after sitting overnight the moosing has completely dissapeared. I cleaned it less than a week ago, so I'll give it some time before calling it a complete success.
