Questions about cleaning

[Nitro Zeus]

I have found out that one should have all parts cleaned in order to have his prayer accepted.

1) If I have a very very small drop of pee in my underwear, I can continue my prayer or I should change my underwear? What should I do?

2) If something unclean has touched a person's legs, and later on has dried out, then he can still pray without cleaning? Or he should still clean no matter what?

Can you please explain how it is done this?

[AbdurRahman.]

If in your estimation or visibly* the impurity has not spread more than the space the size of a UK £2 coin, anywhere on your body or clothes, then you can pray with that as it's not considered unclean.

Obviously if the drop comes out of your body then that will break wudhu, however if it hasn't tainted more than the space specified above, there is no need to wash that area, as per the Hanafi madhab

* you should visually inspect the effected area where possible

[MazharShafiq]

if the drop comes out of your body then that will break wudhu, however if it hasn't tainted more than the space specified above, there is no need to wash that area, as per the Hanafi madhab

* you should visually inspect the effected area where possible

[Nitro Zeus]

if the drop comes out of your body then that will break wudhu, however if it hasn't tainted more than the space specified above, there is no need to wash that area, as per the Hanafi madhab

* you should visually inspect the effected area where possible

So if a drop is there, then I can only way that area and not to make ablution? Or, I should make ablution?