If you are like me, you don't have money to throw at all the extras for your builds. I get scratching material from old bank/credit cards, the little containers that your jelly comes in at the resturant, (plastic and aluminum), old ball-point pens...
Study the picts of your subject, then break it down to basic shapes. For 1/72nd you don't need to get crazy, just get the size and shape right and let the paint do its magic.