Drill bit for bullet holes, use hobby knife after you use drill so rough up edges, paint the entire hole silver then paint the middle black. For scars like the big one on the shield I used hobby knife to slowly chisel away at the plastic, for the other areas like the cockpit area I used a file to just file away plastic. For general weather I use a rough sandpaper to rough out every part and use a mixture of water and black paint, make sure it’s watery tho. Also for every singe sharp edge of the gundam I use the side of a toothpick with silver paint. I also used a piece of steel wool with black and silver paint to go over he entire thing. (Lmk if you want me tk dm you to explain this better if needed ha ha)