Perhaps it is dependent on make & model - I have a 2.1 digifant.
At the bottom of the air intake - (the suction pipe which draws air in
toward the filter), there is a clear plastic fitting which clips to the base
of the suction pipe.  This plastic piece acts like a sump and collects sands
and grits sucked into the intake.
I can provide a photo if you would like.

BT
On Sat, May 21, 2011 at 9:42 AM, <mcneely4@cox.net> wrote:

> ---- Bruce Todd <beeceetee@GMAIL.COM> wrote:
> > If it hasn't been done already make sure you clean your air filter,
> filter
> > assembly and dirt trap from any sand blast material...I had a fair amount
> in
> > the trap when my van came back from the shop.
>
> What is the "dirt trap"?  I know what the air filter and air filter
> assembly are, but have never heard of the "dirt trap" (on this or any other
> vehicle).  It sounds like something that should definitely be cleaned on
> occasion.  I do not find it mentioned in the owner's book, either.
>
> fishman
>