Lettering, numbers, pictures that are part of a cookie or cake itself. (It's all one dough).
Is One Allowed to Rinse Off the Dishes if They Know They Will Attract Bugs or Start to Smell?;
fixing a Hat, Dust on a Hat, a Dent in an Aluminum Foil Pan, Plastic Fruit Cup, and Shaking Down a Thermometer;
How to Work with the Light in the Refrigerator on Shabbos. Part 1;