There's a company called Saggy Bottoms or Baggy Bottoms or something like that that makes inserts that you can purchase. OR you can cut up an old worn out cutting board, use a couple layers of plastic canvas, cardboard, a very thin piece of hobby plywood, etc. I make a pocket the the bottom of my bags with a velcro closure to hold this insert. That way I can take it out before washing. Just make sure the velcro goes from side to side so that coins and other things can't hide in there.