When an outlet is overloaded regularly the heat overtime can cause the metal to breakdown and melt plastic. Because the ground strip is most likely displacing the heat to the screws that’s why you are seeing the the burn marks on the screws. More then likely the connections are in rough shape and causing higher temperatures due to arcing but still not to ground which would cause the breaker to trip. The wires and insulation will likely have some damage as well. If you are not sure how to properly assess the damage you should have an electrician take a look. But you certainly should keep the power off on it and not use this outlet. If you have wire nuts and feel comfortable you can turn the power off and remove the outlet and cap the wires but you will likely want to trim off the burnt wire and insulation. If this outlet is feeding others which it likely is depending on how you do it you may lose power to down stream outlets. If you feel mechanically inclined to do this maybe post some more pictures if you aren’t sure what to do with the wiring.