I cut a piece of mesh larger than the opening and wedged it in place from underneath the bumper. Then I used some zip-ties to keep it in place in case it ever comes loose. That was over a year ago and no problems.
2000 Contour SE 2.5L ATX - Toreador Red
2001 VW Golf GLS 2.0L MTX - Tornado Red
Buy my possessed VCR!!