Is everything that exits the two passages ritually impure, and how can one distinguish between that which is ruled impure due to its contact with urine and that which is not?

The basic principle is that everything that exits from the two private parts (front and back) is impure, except for that which is proven to be pure by evidence. The following are exceptions:

1. That which is not liquid: such as worms and stones. These are pure as long as they are not contaminated with impurity.

2. Wind: It is pure.

3. Semen: It is pure, according to the preponderant opinion of scholars. However, if it encounters impurity on its way out, it becomes defiled by it.

4. Vaginal fluids of women: Their purity is the preponderant opinion.