Here are two magnet free suggestions:

Mine: Cut out a piece of board to the size of the glass opening minus
a couple of cm on the bottom. Cut out the inside of the board to make
a 2-3cm wide frame. Glue bug netting into the board.

Insert in to window frame and crank window up to put pressure on it
to hold it in.

I made several of these. A bit tedious cutting work.

Angel's (I think he said this is a VW idea though):
Cut the bug netting several inches bigger than the top of the door.
Fold over and sew an elastic around the inside edges.
Drape/Clothe the netting over the door. Close door and the net
is jammed between the door and body.

/Martin
--
New and used parts for sale, gas and Diesel:

    http://www.cs.yale.edu/~jag/vw/forsale.html

Westy 1.9l Turbo Diesel
Quantum 1.6l Turbo Diesel

Martin Jagersand                 email: jag@cs.yale.edu
Computer Science Department             jag@cs.rochester.edu
Yale University

        Slow down and visit the VW diesel Westy page:
          WWW: http://www.cs.rochester.edu/u/jag/vw
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