Wiping in One Stroke
Question :

Someone told me that when I finish pouring water on my arm, before I start wiping freely, I must wipe once from my elbow down to my fingertips in one stroke and if this is not done then the wudhu is void. Is this true?

Answer :

No, it is not true. You can do so with as many strokes as necessary to ensure that the area is fully washed.

Pouring Water on the Arm
Question :

When performing wudhu, do I have to pour water on the back of my arms or from the front?

Answer :

Both ways of washing the arms are permissible.

Nail Polish
Question :

Can a girl still pray while she has colored nail polish on fingers and/or toes?

Answer :

Having nail polish is permissible during the prayer if it was applied after wudhu or ghusl. It prevents water from reaching the nail so it invalidates wudhu or ghusl if it was applied before performing any one of them. It can be applied on some of the toes that are not wiped during wudhu.

Dirts under the Nail
Question :

Is a bit of dirt and such similar substances that are usually found under the nail or on its sides considered a barrier during wudhu and ghusl?

Answer :

It is not a condition in the correctness of wudhu or ghusl to remove what is underneath the nail. Dirt that appears on the nail or on its sides must be removed for the wudhu and ghusl to be correct.

Dirt Under the Fingernails
Question :

Sometimes I doubt as to whether the dirt under the fingernails is extended to the outside of the nail or not, which would then require me to remove it before performing wudhu, moreover it is very hard to remove it sometimes. Can I ignore this doubt?

Answer :

It is not obligatory to remove the dirt under the nail, since this area is not part of wudhu or ghusl. If the dirt prevents water from reaching the skin in parts of wudhu and ghusl, it must be removed; one can use material that removes such substances in the conventional way, and one need not focus on this beyond that.
However, if a person has a reasonable doubt whether there is any substance that is forming a barrier between the water and the skin, then he should remove it to ensure that water reaches the skin.