Take the cabinet doors off the hinges and lay them down on a flat surface. Use a screwdriver or a hammer to pry the pins from the hinges.
Remove any hardware and clear plastic clips holding the glass in place. Slide the glass up or down slightly, and remove it from the door.
Pry the old rubber seal or insert from the cabinet door with a utility knife. Carefully cut the deteriorated seal and pull it out of the groove.
Insert the new notched rubber glass or panel insert, or seal, into the groove in the cabinet door. Press the rubber seal into the groove until if fits snugly inside the channel.
Replace the glass in the doors and attach any plastic clips to hold the pane in place. Reinstall the hardware and hang the doors back on their hinges.