Well, I can't find the post I am looking for, but I could swear that someone once posted a link to an online store that carried covers that cover be intered over or in the vent to stop the airflow (which would also stop the suggie from getting in it!). I try a few searches again, but until then,
this post had a suggestion that may help you. <img src="/ubbthreads/images/graemlins/cool.gif" alt="" />