In an introductory note to this chapter, the Kitzur Shulchan Aruch writes that most Jews are already familiar with the prohibited labors of Shabbos and that he is only addressing common situations with which people may not be familiar. Clearly, the laws of Shabbos constitute an area requiring much greater study than this email alone will allow.
80:41 If a person gets mud on his hands, he may not wipe it off using a towel that is normally used for drying one’s hands. This is because of the concern that one will come to wash the towel. (One may use a rag – Mishnah Brurah 302:57.)
80:42 One may not dye anything on Shabbos, even with a non-permanent dye. Therefore, a woman may not color her face (with make-up) on Shabbos. If a person’s hands become stained with fruit juice, he must be careful not to touch his clothes because this will color them. Similarly, one may not wipe blood from a nosebleed or a cut with a cloth. (If no appropriate alternative is available, one may be lenient with both blood and fruit juice - Mishnah Brurah 328:146 and 320:59, respectively.)