Tahaarat

Leftover milk of a dog and cat

Q: Please may the general ruling on 'circumstantial evidence' relating to the Soor (leftover) of animals be explained. I heard an example of a bowl of milk and a dog, but I cannot remember the particulars. We have cats at home and I am unsure when to consider something pure or as makrooh soor (leftover). If appropriate, please may the milk/dog example also be given.

Food getting stuck in dental cavities

Q:

1. I have cavities in my tooth, and when I eat, food gets stuck. When I rinse my mouth or use miswak, it's still stuck. But when I brush my teeth, it easily comes out. Should I brush my teeth before I perform wudhu everytime I eat, or is it okay for the food to be stuck in the cavities?

2. Is it permissible to have dental fillings so that food doesn't get stuck, or is the filling regarded the same as stuck food? If it is permissible, is there any specific type which should be used as a filling? For example, the fillings come in gold, porcelain, a composite resin (tooth-colored fillings), and an amalgam (an alloy of mercury, silver, copper, tin and sometimes zinc).

3. Sometimes, the food eaten comes back to mouth unintentionally. When this happens, does wudhu break? What about fast?

Masturbation

Q: After urinating, when rinsing the private area with a hand shower, the pressure of the water is satisfying. Sometimes, I get really aroused, which follows a discharge. Is this counted as masturbation? Do I have to perform ghusl?