Making a Bruise or Using a Toothbrush When One's Gums Might Bleed. Using Floss, Toothpicks, and Dealing with Blood from a Cut;
The Proper Procedure for Checking One's Blood on Shabbos (e.g., for Diabetics);
Planting or Walking with Wet Peios/Raincoats over Grass; How to Handle Very Wet Grassy Ground;