Using bottle caps, boxes, packages with lettering, numbers, or pictures on them.
how to work with paper towels, napkins, tissues, toilet paper on Shabbos;
Introduction to How the Melacha of M'abaid Applies to Foods;
ממצוא חפציך (Mimtzo Cheftzecha): What Type of Instances Would Make These Actions Allowed to Be Done on Shabbos?;