I developed a rattle in my dash, and it was driving me nuts. So
today I went for a helmetless, earplugless ride down a country road
here at the farm. I pushed, pulled, held, and squeezed various pieces
of the dash until I figured out where it was coming from.
Turns out it was between the silver trim piece and the black part
behind it. The two pieces were touching at the bottom as shown
in this picture...

The solution was to either place something between the two pieces
to stop the rattle, or to increase the distance between the two
pieces, which would alleviate the contact between the two surfaces.
I chose the latter.
I decided to place some washers at the back of the trim piece to
increase the spacing. The problem with this is that I would not
be able to hold them in place while I reassembled everything because
there was no way for me to get my fingers in the small places where
the screws go...

So I placed two little washers on the back side of the dash trim
piece as shown (though blurry) below...

I then taped them in place using electrical tape. For good
measure, I used a tiny zip tie to stop the tape from coming unraveled
through wind and weather...

Here's a picture (again blurry, sorry) of the washers taped in
place and the screw protruding though...

When reassembled, you can see there is a gap between the two pieces
now...

Test ride...
... rattle gone.
I thought I would share.