I use vinyl flooring scraps, can cut easily with a used rotary blade that no longer will cut fabric. I put it inside between the lining and outer fabric (I use a few dabs of E6000 on the corners and center, drop thick books inside purse overnight), then pull up lining and hand or machine stitch opening closed. Others I will have it removeable by covering with a sleeve. Get scraps from flooring places or I have found in thrift shops also. The thicker kind works best. If washing with vinyl inside, I recommend hand wash & air dry. If removable, can machine wash the purse & hand wash the sleeve. Cheap & sturdy!