Great idea. I placed one along the front edge, but the metal lid still comes down with a heavy thud. Placing more towards the back, so it almost pinches at the hinge point might help.

I should have added in the post - the main reason for this is to quiet the box as much as possible to help reduce reactions from our dog we rescued this year. New mailman last month, who lets the lid slam and then walks along our porch by the windows, leading to a reaction from our dog. He's been getting a training session almost every day, for various behavior/obedience, but I'm looking for an assist to help with mailman reactivity.