15.7" x 59" Extra Large Cuttable Air Conditioner Filters - Cut to Fit Carbon Pad Air Purifier Filters, Washable Reusable Foam Pad Pre Filter Roll for Air Filters AC Window Unit Charcoal Sheet

Yes, that's what I meant! You'd order a foam filter that's around 0.25" thick, so something like this To install it, just pull open the removable front panel like you normally would to clean it. Cut a piece of the foam to match the dimensions of the interior of the front panel, and place it either in front of the mesh filter, or inside the front panel. Once you've got it in place, just close the front panel up like normal. Any foam that might not be completely in place will just squish down, so it's not a big deal if it isn't a perfect fit. Doing this makes it so the mesh filter hardly gets anything on it at all because the foam catches the vast majority of the dust.