The best and cheapest way I found is buy a pre-filter for a shop vac and a cheap hot glue gun. It took me about a 1/2 hr. to cut and glue the material for the first one I did and 10 minutes for others after that. I think the pre-filter cost around $6 and maybe $10 for the hot glue gun. It's held up well as I'm on the 3rd season doing this.View attachment 65944